diff --git a/08_calculator/calculator.spec.js b/08_calculator/calculator.spec.js
index 48b08c9cb70..72152f7f45d 100644
--- a/08_calculator/calculator.spec.js
+++ b/08_calculator/calculator.spec.js
@@ -18,6 +18,14 @@ describe('subtract', () => {
   test.skip('subtracts numbers', () => {
     expect(calculator.subtract(10, 4)).toBe(6);
   });
+
+  test.skip('subtracts negative numbers', () => {
+    expect(calculator.subtract(-10, -4)).toBe(-6);
+  });
+
+  test.skip('subtracts numbers of mixed parity', () => {
+    expect(calculator.subtract(-8, 7)).toBe(-15);
+  });
 });
 
 describe('sum', () => {
@@ -52,6 +60,10 @@ describe('power', () => {
   test.skip('raises one number to the power of another number', () => {
     expect(calculator.power(4, 3)).toBe(64); // 4 to third power is 64
   });
+
+  test.skip('raises one number to the power of a large number', () => {
+    expect(calculator.power(3, 10)).toBe(59049); // 3 to tenth power is 59049
+  });
 });
 
 describe('factorial', () => {
diff --git a/08_calculator/solution/calculator-solution.spec.js b/08_calculator/solution/calculator-solution.spec.js
index 453707ce527..4d0770238da 100644
--- a/08_calculator/solution/calculator-solution.spec.js
+++ b/08_calculator/solution/calculator-solution.spec.js
@@ -18,6 +18,14 @@ describe('subtract', () => {
   test('subtracts numbers', () => {
     expect(calculator.subtract(10, 4)).toBe(6);
   });
+
+  test('subtracts negative numbers', () => {
+    expect(calculator.subtract(-10, -4)).toBe(-6);
+  });
+
+  test('subtracts numbers of mixed parity', () => {
+    expect(calculator.subtract(-8, 7)).toBe(-15);
+  });
 });
 
 describe('sum', () => {
@@ -52,6 +60,10 @@ describe('power', () => {
   test('raises one number to the power of another number', () => {
     expect(calculator.power(4, 3)).toBe(64); // 4 to third power is 64
   });
+
+  test('raises one number to the power of a large number', () => {
+    expect(calculator.power(3, 10)).toBe(59049); // 3 to tenth power is 59049
+  });
 });
 
 describe('factorial', () => {