diff --git a/CHANGELOG.md b/CHANGELOG.md
index 699dab9..86d9872 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -85,9 +85,13 @@
 - Average collection function added
 - Min collection function added
 - Max collection function added
-- ToArrray collection function added
+- ToString collection function added
 - **Breaking change: sum utility function removed**
 - **Breaking change: average utility function removed**
 - **Breaking change: min utility function removed**
 - **Breaking change: max utility function removed**
 - **Breaking change: concatenate utility function removed**
+
+##8.0.0
+- **Breaking change: sum function will return integer by default, float if there are float type elements**
+- **Breaking change: average function will not force return float and will return integer if the sum/count result is integer**
diff --git a/composer.json b/composer.json
index 35d47c8..6cf2d6e 100644
--- a/composer.json
+++ b/composer.json
@@ -14,13 +14,13 @@
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-    "ciaranmcnulty/phpspec-typehintedmethods": "*",
-    "phpunit/phpunit": "4.5.*",
-    "symfony/console": "~2.7"
+    "phpspec/phpspec": "^2.0",
+    "henrikbjorn/phpspec-code-coverage": "^2.0",
+    "squizlabs/php_codesniffer": "^2.0",
+    "phpmd/phpmd" : "^2.0",
+    "ciaranmcnulty/phpspec-typehintedmethods": "^1.0",
+    "phpunit/phpunit": "^5.0",
+    "symfony/console": "^2.7"
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diff --git a/composer.lock b/composer.lock
index 8392349..37346de 100644
--- a/composer.lock
+++ b/composer.lock
@@ -4,8 +4,8 @@
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@@ -112,28 +112,28 @@
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+            "version": "2.1.0",
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-                "reference": "121720787a390be78e307916313e9f225a39d803"
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-                "reference": "121720787a390be78e307916313e9f225a39d803",
+                "url": "https://api.github.com/repos/henrikbjorn/PhpSpecCodeCoverageExtension/zipball/528a0c69a524f8acba5f66bc59ae8dc9bc409045",
+                "reference": "528a0c69a524f8acba5f66bc59ae8dc9bc409045",
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+                "php": "^5.3.3|^5.4|^5.5|^5.6|^7.0",
                 "phpspec/phpspec": "^2.0",
-                "phpunit/php-code-coverage": "^3|2.2.4"
+                "phpunit/php-code-coverage": "^2.2.4|^3"
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             },
             "suggest": {
-                "ext-xdebug": "To allow Coverage generation."
+                "ext-xdebug": "To allow coverage generation when not using a recent version of phpdbg"
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@@ -151,38 +151,81 @@
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-            "time": "2016-02-02 08:26:28"
+            "time": "2016-05-05 18:25:12"
+        },
+        {
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+            "version": "1.5.1",
+            "source": {
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+                "reference": "a8773992b362b58498eed24bf85005f363c34771"
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+            },
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+            },
+            "require-dev": {
+                "doctrine/collections": "1.*",
+                "phpunit/phpunit": "~4.1"
+            },
+            "type": "library",
+            "autoload": {
+                "psr-4": {
+                    "DeepCopy\\": "src/DeepCopy/"
+                }
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "MIT"
+            ],
+            "description": "Create deep copies (clones) of your objects",
+            "homepage": "https://github.com/myclabs/DeepCopy",
+            "keywords": [
+                "clone",
+                "copy",
+                "duplicate",
+                "object",
+                "object graph"
+            ],
+            "time": "2015-11-20 12:04:31"
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+            "version": "2.2.4",
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-                "symfony/dependency-injection": ">=2.4",
-                "symfony/filesystem": ">=2.4"
+                "php": ">=5.3.7",
+                "symfony/config": "^2.3.0|^3",
+                "symfony/dependency-injection": "^2.3.0|^3",
+                "symfony/filesystem": "^2.3.0|^3"
             },
             "require-dev": {
-                "phpunit/phpunit": "4.*@stable",
-                "squizlabs/php_codesniffer": "@stable"
+                "phpunit/phpunit": "^4.4.0,<4.8",
+                "squizlabs/php_codesniffer": "^2.0.0"
             },
             "bin": [
                 "src/bin/pdepend"
             ],
             "type": "library",
             "autoload": {
-                "psr-0": {
-                    "PDepend\\": "src/main/php/"
+                "psr-4": {
+                    "PDepend\\": "src/main/php/PDepend"
                 }
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@@ -190,7 +233,7 @@
                 "BSD-3-Clause"
             ],
             "description": "Official version of pdepend to be handled with Composer",
-            "time": "2015-03-02 08:06:43"
+            "time": "2016-03-10 15:15:04"
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@@ -243,28 +286,25 @@
         },
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-            "version": "2.2.1",
+            "version": "2.4.3",
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                 "url": "https://github.com/phpmd/phpmd.git",
-                "reference": "58c4b00f924d301e8c5281f40cfa9a66f3df9eee"
+                "reference": "2b9c2417a18696dfb578b38c116cd0ddc19b256e"
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-                "reference": "58c4b00f924d301e8c5281f40cfa9a66f3df9eee",
+                "url": "https://api.github.com/repos/phpmd/phpmd/zipball/2b9c2417a18696dfb578b38c116cd0ddc19b256e",
+                "reference": "2b9c2417a18696dfb578b38c116cd0ddc19b256e",
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-                "symfony/config": ">=2.4",
-                "symfony/dependency-injection": ">=2.4",
-                "symfony/filesystem": ">=2.4"
+                "pdepend/pdepend": "^2.0.4",
+                "php": ">=5.3.0"
             },
             "require-dev": {
-                "phpunit/phpunit": "*",
-                "squizlabs/php_codesniffer": "*"
+                "phpunit/phpunit": "^4.0",
+                "squizlabs/php_codesniffer": "^2.0"
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@@ -284,12 +324,18 @@
                     "name": "Manuel Pichler",
                     "email": "github@manuel-pichler.de",
                     "homepage": "https://github.com/manuelpichler",
-                    "role": "Project founder"
+                    "role": "Project Founder"
                 },
                 {
                     "name": "Other contributors",
                     "homepage": "https://github.com/phpmd/phpmd/graphs/contributors",
                     "role": "Contributors"
+                },
+                {
+                    "name": "Marc Würth",
+                    "email": "ravage@bluewin.ch",
+                    "homepage": "https://github.com/ravage84",
+                    "role": "Project Maintainer"
                 }
             ],
             "description": "PHPMD is a spin-off project of PHP Depend and aims to be a PHP equivalent of the well known Java tool PMD.",
@@ -301,7 +347,7 @@
                 "phpmd",
                 "pmd"
             ],
-            "time": "2015-03-02 10:26:50"
+            "time": "2016-04-04 11:52:04"
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@@ -479,39 +525,40 @@
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-            "version": "2.2.4",
+            "version": "3.3.3",
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+                "php": "^5.6 || ^7.0",
                 "phpunit/php-file-iterator": "~1.3",
                 "phpunit/php-text-template": "~1.2",
-                "phpunit/php-token-stream": "~1.3",
+                "phpunit/php-token-stream": "^1.4.2",
+                "sebastian/code-unit-reverse-lookup": "~1.0",
                 "sebastian/environment": "^1.3.2",
-                "sebastian/version": "~1.0"
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-                "phpunit/phpunit": "~4"
+                "phpunit/phpunit": "~5"
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@@ -537,35 +584,37 @@
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-            "time": "2015-10-06 15:47:00"
+            "time": "2016-05-27 16:24:29"
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@@ -582,7 +631,7 @@
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-            "time": "2013-10-10 15:34:57"
+            "time": "2015-06-21 13:08:43"
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@@ -627,21 +676,24 @@
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-            "version": "1.0.7",
+            "version": "1.0.8",
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+            },
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@@ -664,7 +716,7 @@
             "keywords": [
                 "timer"
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-            "time": "2015-06-21 08:01:12"
+            "time": "2016-05-12 18:03:57"
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@@ -717,16 +769,16 @@
         },
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-            "version": "4.5.1",
+            "version": "5.3.4",
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@@ -735,20 +787,23 @@
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-                "phpunit/php-code-coverage": "~2.0,>=2.0.11",
-                "phpunit/php-file-iterator": "~1.3.2",
+                "myclabs/deep-copy": "~1.3",
+                "php": "^5.6 || ^7.0",
+                "phpspec/prophecy": "^1.3.1",
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-                "phpunit/php-timer": "~1.0.2",
-                "phpunit/phpunit-mock-objects": "~2.3",
+                "phpunit/php-timer": "^1.0.6",
+                "phpunit/phpunit-mock-objects": "^3.1",
                 "sebastian/comparator": "~1.1",
-                "sebastian/diff": "~1.1",
-                "sebastian/environment": "~1.2",
+                "sebastian/diff": "~1.2",
+                "sebastian/environment": "~1.3",
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                 "sebastian/global-state": "~1.0",
-                "sebastian/version": "~1.0",
-                "symfony/yaml": "~2.0"
+                "sebastian/object-enumerator": "~1.0",
+                "sebastian/resource-operations": "~1.0",
+                "sebastian/version": "~1.0|~2.0",
+                "symfony/yaml": "~2.1|~3.0"
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@@ -759,7 +814,7 @@
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@@ -785,30 +840,30 @@
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-            "time": "2015-03-29 09:24:05"
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-                "sebastian/exporter": "~1.2"
+                "php": "^5.6 || ^7.0",
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+                "sebastian/exporter": "^1.2"
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+                "phpunit/phpunit": "^5.4"
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@@ -816,7 +871,7 @@
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@@ -841,7 +896,52 @@
                 "mock",
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-            "time": "2015-10-02 06:51:40"
+            "time": "2016-06-03 05:01:30"
+        },
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+            "version": "1.0.0",
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+                "shasum": ""
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+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Looks up which function or method a line of code belongs to",
+            "homepage": "https://github.com/sebastianbergmann/code-unit-reverse-lookup/",
+            "time": "2016-02-13 06:45:14"
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@@ -961,16 +1061,16 @@
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         {
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-            "version": "1.3.5",
+            "version": "1.3.7",
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                 "url": "https://github.com/sebastianbergmann/environment.git",
-                "reference": "dc7a29032cf72b54f36dac15a1ca5b3a1b6029bf"
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-                "reference": "dc7a29032cf72b54f36dac15a1ca5b3a1b6029bf",
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             "require": {
@@ -1007,7 +1107,7 @@
                 "environment",
                 "hhvm"
             ],
-            "time": "2016-02-26 18:40:46"
+            "time": "2016-05-17 03:18:57"
         },
         {
             "name": "sebastian/exporter",
@@ -1126,6 +1226,52 @@
             ],
             "time": "2015-10-12 03:26:01"
         },
+        {
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+            "version": "1.0.0",
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+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/object-enumerator.git",
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+                "shasum": ""
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+            "require": {
+                "php": ">=5.6",
+                "sebastian/recursion-context": "~1.0"
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+            "require-dev": {
+                "phpunit/phpunit": "~5"
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+                    "dev-master": "1.0.x-dev"
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+            "autoload": {
+                "classmap": [
+                    "src/"
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+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
+                "BSD-3-Clause"
+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Traverses array structures and object graphs to enumerate all referenced objects",
+            "homepage": "https://github.com/sebastianbergmann/object-enumerator/",
+            "time": "2016-01-28 13:25:10"
+        },
         {
             "name": "sebastian/recursion-context",
             "version": "1.0.2",
@@ -1179,21 +1325,71 @@
             "homepage": "http://www.github.com/sebastianbergmann/recursion-context",
             "time": "2015-11-11 19:50:13"
         },
+        {
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+            "version": "1.0.0",
+            "source": {
+                "type": "git",
+                "url": "https://github.com/sebastianbergmann/resource-operations.git",
+                "reference": "ce990bb21759f94aeafd30209e8cfcdfa8bc3f52"
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+            "require": {
+                "php": ">=5.6.0"
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+            "type": "library",
+            "extra": {
+                "branch-alias": {
+                    "dev-master": "1.0.x-dev"
+                }
+            },
+            "autoload": {
+                "classmap": [
+                    "src/"
+                ]
+            },
+            "notification-url": "https://packagist.org/downloads/",
+            "license": [
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+            ],
+            "authors": [
+                {
+                    "name": "Sebastian Bergmann",
+                    "email": "sebastian@phpunit.de"
+                }
+            ],
+            "description": "Provides a list of PHP built-in functions that operate on resources",
+            "homepage": "https://www.github.com/sebastianbergmann/resource-operations",
+            "time": "2015-07-28 20:34:47"
+        },
         {
             "name": "sebastian/version",
-            "version": "1.0.6",
+            "version": "2.0.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/sebastianbergmann/version.git",
-                "reference": "58b3a85e7999757d6ad81c787a1fbf5ff6c628c6"
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+            },
             "autoload": {
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@@ -1212,20 +1408,20 @@
             ],
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             "homepage": "https://github.com/sebastianbergmann/version",
-            "time": "2015-06-21 13:59:46"
+            "time": "2016-02-04 12:56:52"
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         {
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-            "version": "2.6.0",
+            "version": "2.6.1",
             "source": {
                 "type": "git",
                 "url": "https://github.com/squizlabs/PHP_CodeSniffer.git",
-                "reference": "1bcdf03b068a530ac1962ce671dead356eeba43b"
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@@ -1290,20 +1486,20 @@
                 "phpcs",
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-            "time": "2016-04-03 22:58:34"
+            "time": "2016-05-30 22:24:32"
         },
         {
             "name": "symfony/config",
-            "version": "v3.0.4",
+            "version": "v3.1.0",
             "source": {
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                 "url": "https://github.com/symfony/config.git",
-                "reference": "980ee40c28f00acff8906c11b778aab5f0db74c2"
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@@ -1316,7 +1512,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "3.1-dev"
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@@ -1343,20 +1539,20 @@
             ],
             "description": "Symfony Config Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-04 07:55:57"
+            "time": "2016-05-20 11:48:17"
         },
         {
             "name": "symfony/console",
-            "version": "v2.8.4",
+            "version": "v2.8.6",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/console.git",
-                "reference": "9a5aef5fc0d4eff86853d44202b02be8d5a20154"
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@@ -1403,20 +1599,20 @@
             ],
             "description": "Symfony Console Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-17 09:19:04"
+            "time": "2016-04-26 12:00:47"
         },
         {
             "name": "symfony/dependency-injection",
-            "version": "v3.0.4",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/dependency-injection.git",
-                "reference": "6a9058101b591edced21ca3c83c80a3978f5c6b0"
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             "require": {
@@ -1429,13 +1625,14 @@
             },
             "suggest": {
                 "symfony/config": "",
+                "symfony/expression-language": "For using expressions in service container configuration",
                 "symfony/proxy-manager-bridge": "Generate service proxies to lazy load them",
                 "symfony/yaml": ""
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "3.1-dev"
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             "autoload": {
@@ -1462,20 +1659,20 @@
             ],
             "description": "Symfony DependencyInjection Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-30 10:41:14"
+            "time": "2016-05-24 10:06:56"
         },
         {
             "name": "symfony/event-dispatcher",
-            "version": "v3.0.4",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/event-dispatcher.git",
-                "reference": "9002dcf018d884d294b1ef20a6f968efc1128f39"
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-                "reference": "9002dcf018d884d294b1ef20a6f968efc1128f39",
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@@ -1495,7 +1692,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "3.1-dev"
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@@ -1522,20 +1719,20 @@
             ],
             "description": "Symfony EventDispatcher Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-10 10:34:12"
+            "time": "2016-04-12 18:27:47"
         },
         {
             "name": "symfony/filesystem",
-            "version": "v3.0.4",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/filesystem.git",
-                "reference": "f82499a459dcade2ea56df94cc58b19c8bde3d20"
+                "reference": "5751e80d6f94b7c018f338a4a7be0b700d6f3058"
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-                "reference": "f82499a459dcade2ea56df94cc58b19c8bde3d20",
+                "url": "https://api.github.com/repos/symfony/filesystem/zipball/5751e80d6f94b7c018f338a4a7be0b700d6f3058",
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@@ -1544,7 +1741,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "3.1-dev"
                 }
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             "autoload": {
@@ -1571,20 +1768,20 @@
             ],
             "description": "Symfony Filesystem Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-27 10:24:39"
+            "time": "2016-04-12 18:27:47"
         },
         {
             "name": "symfony/finder",
-            "version": "v3.0.4",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/finder.git",
-                "reference": "c54e407b35bc098916704e9fd090da21da4c4f52"
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-                "reference": "c54e407b35bc098916704e9fd090da21da4c4f52",
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@@ -1593,7 +1790,7 @@
             "type": "library",
             "extra": {
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+                    "dev-master": "3.1-dev"
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             "autoload": {
@@ -1620,20 +1817,20 @@
             ],
             "description": "Symfony Finder Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-10 11:13:05"
+            "time": "2016-05-13 18:06:41"
         },
         {
             "name": "symfony/polyfill-mbstring",
-            "version": "v1.1.1",
+            "version": "v1.2.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/polyfill-mbstring.git",
-                "reference": "1289d16209491b584839022f29257ad859b8532d"
+                "reference": "dff51f72b0706335131b00a7f49606168c582594"
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-                "reference": "1289d16209491b584839022f29257ad859b8532d",
+                "url": "https://api.github.com/repos/symfony/polyfill-mbstring/zipball/dff51f72b0706335131b00a7f49606168c582594",
+                "reference": "dff51f72b0706335131b00a7f49606168c582594",
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@@ -1645,7 +1842,7 @@
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             "extra": {
                 "branch-alias": {
-                    "dev-master": "1.1-dev"
+                    "dev-master": "1.2-dev"
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             "autoload": {
@@ -1679,20 +1876,20 @@
                 "portable",
                 "shim"
             ],
-            "time": "2016-01-20 09:13:37"
+            "time": "2016-05-18 14:26:46"
         },
         {
             "name": "symfony/process",
-            "version": "v3.0.4",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/process.git",
-                "reference": "e6f1f98bbd355d209a992bfff45e7edfbd4a0776"
+                "reference": "1574f3451b40fa9bbae518ef71d19a56f409cac0"
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-                "reference": "e6f1f98bbd355d209a992bfff45e7edfbd4a0776",
+                "url": "https://api.github.com/repos/symfony/process/zipball/1574f3451b40fa9bbae518ef71d19a56f409cac0",
+                "reference": "1574f3451b40fa9bbae518ef71d19a56f409cac0",
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@@ -1701,7 +1898,7 @@
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "3.0-dev"
+                    "dev-master": "3.1-dev"
                 }
             },
             "autoload": {
@@ -1728,29 +1925,29 @@
             ],
             "description": "Symfony Process Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-30 10:41:14"
+            "time": "2016-04-12 19:11:33"
         },
         {
             "name": "symfony/yaml",
-            "version": "v2.8.4",
+            "version": "v3.1.0",
             "source": {
                 "type": "git",
                 "url": "https://github.com/symfony/yaml.git",
-                "reference": "584e52cb8f788a887553ba82db6caacb1d6260bb"
+                "reference": "eca51b7b65eb9be6af88ad7cc91685f1556f5c9a"
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             "dist": {
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-                "reference": "584e52cb8f788a887553ba82db6caacb1d6260bb",
+                "url": "https://api.github.com/repos/symfony/yaml/zipball/eca51b7b65eb9be6af88ad7cc91685f1556f5c9a",
+                "reference": "eca51b7b65eb9be6af88ad7cc91685f1556f5c9a",
                 "shasum": ""
             },
             "require": {
-                "php": ">=5.3.9"
+                "php": ">=5.5.9"
             },
             "type": "library",
             "extra": {
                 "branch-alias": {
-                    "dev-master": "2.8-dev"
+                    "dev-master": "3.1-dev"
                 }
             },
             "autoload": {
@@ -1777,7 +1974,7 @@
             ],
             "description": "Symfony Yaml Component",
             "homepage": "https://symfony.com",
-            "time": "2016-03-04 07:54:35"
+            "time": "2016-05-26 21:46:24"
         }
     ],
     "aliases": [],
diff --git a/src/CollectionTrait.php b/src/CollectionTrait.php
index 8c126b3..27a694e 100644
--- a/src/CollectionTrait.php
+++ b/src/CollectionTrait.php
@@ -809,7 +809,7 @@ public function sizeIsBetween($fromSize, $toSize)
     /**
      * Returns a sum of all values in this collection.
      *
-     * @return float
+     * @return int|float
      */
     public function sum()
     {
@@ -819,7 +819,7 @@ public function sum()
     /**
      * Returns average of values from this collection.
      *
-     * @return float
+     * @return int|float
      */
     public function average()
     {
diff --git a/src/collection_functions.php b/src/collection_functions.php
index 33677de..05b5cc2 100644
--- a/src/collection_functions.php
+++ b/src/collection_functions.php
@@ -1521,11 +1521,11 @@ function sizeIsBetween($collection, $fromSize, $toSize)
  * Returns a sum of all values in the $collection.
  *
  * @param array|Traversable $collection
- * @return float
+ * @return int|float
  */
 function sum($collection)
 {
-    $result = 0.0;
+    $result = 0;
 
     foreach ($collection as $value) {
         $result += $value;
@@ -1538,11 +1538,11 @@ function sum($collection)
  * Returns average of values from $collection.
  *
  * @param array|Traversable $collection
- * @return float
+ * @return int|float
  */
 function average($collection)
 {
-    $sum = 0.0;
+    $sum = 0;
     $count = 0;
 
     foreach ($collection as $value) {
@@ -1550,7 +1550,7 @@ function average($collection)
         $count++;
     }
 
-    return $count ? (float) $sum/$count : 0.0;
+    return $count ? $sum/$count : 0;
 }
 
 /**
diff --git a/tests/spec/CollectionSpec.php b/tests/spec/CollectionSpec.php
index d138517..f974be8 100644
--- a/tests/spec/CollectionSpec.php
+++ b/tests/spec/CollectionSpec.php
@@ -1134,19 +1134,21 @@ function it_can_check_if_size_is_between_n_and_m()
     function it_can_sum_the_collection()
     {
         $this->beConstructedWith([1, 2, 3, 4]);
-        $this->sum()->shouldReturn(10.0);
+        $this->sum()->shouldReturn(10);
+        $this->append(1.5)->sum()->shouldReturn(11.5);
     }
 
     function it_can_get_average_of_the_collection()
     {
         $this->beConstructedWith([1, 2, 2, 3]);
-        $this->average()->shouldReturn(2.0);
+        $this->average()->shouldReturn(2);
+        $this->append(3)->average()->shouldReturn(2.2);
     }
 
     function it_will_return_zero_when_average_is_called_on_empty_collection()
     {
         $this->beConstructedWith([]);
-        $this->average()->shouldReturn(0.0);
+        $this->average()->shouldReturn(0);
     }
 
     function it_can_get_maximal_value_in_the_colleciton()