Arithmetic operators in Javascript - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the + operator do in JavaScript when used with numbers?

It adds two numbers together to produce their sum.

beginner

What is the result of 10 - 4 in JavaScript?

The result is 6, because the - operator subtracts the second number from the first.

beginner

How does the * operator work in JavaScript?

It multiplies two numbers and returns the product.

beginner

What does the / operator do?

It divides the first number by the second number and returns the quotient.

beginner

What is the purpose of the % operator in JavaScript?

It returns the remainder after dividing the first number by the second number, also called the modulus.

What is the result of 7 + 3 * 2 in JavaScript?

A 20

B 16

C 10

D 13

Multiplication happens before addition, so 3 * 2 = 6, then 7 + 6 = 13.

Which operator gives the remainder of a division?

A *

B -

C %

D +

The % operator returns the remainder after division.

What does 15 / 4 return in JavaScript?

A 3

B 3.75

C 4

D 3 remainder 3

JavaScript division returns a floating-point number, so 15 divided by 4 is 3.75.

What is the value of 5 % 2?

A 1

B 2

C 0

D 3

5 divided by 2 leaves a remainder of 1.

Which operator is used to multiply numbers?

A *

B -

C /

D +

The * operator multiplies numbers.

Explain how the order of operations affects arithmetic expressions in JavaScript.

Think about which operations happen first when you see multiple operators.

Describe the difference between the division operator / and the modulus operator %.

One tells you how many times a number fits, the other tells you what's left over.

Practice

1. Which arithmetic operator in JavaScript is used to find the remainder of a division?

easy

A. %

B. /

C. **

D. *

Solution

1. Step 1: Understand the remainder operator

   The operator % returns the remainder after division of two numbers.

2. Step 2: Compare with other operators

   / is division, ** is power, and * is multiplication, so they don't give remainder.

3. Final Answer:

   % -> Option A

4. Quick Check:

   Remainder operator = % [OK]

Hint: Remainder operator looks like a percent sign % [OK]

Common Mistakes:

• Confusing division / with remainder %
• Using * or ** instead of %
• Thinking + or - can give remainder

2. Which of the following is the correct syntax to calculate 5 to the power of 3 in JavaScript?

easy

A. 5 ** 3

B. 5 ^^ 3

C. 5 ^ 3

D. pow(5, 3)

Solution

1. Step 1: Identify the power operator in JavaScript

   JavaScript uses ** to calculate powers, like 5 ** 3 means 5 to the power 3.

2. Step 2: Check other options for correctness

   ^ is bitwise XOR, ^^ is invalid syntax, and pow() is not a built-in function in JavaScript.

3. Final Answer:

   5 ** 3 -> Option A

4. Quick Check:

   Power operator = ** [OK]

Hint: Use ** for power, not ^ or pow() [OK]

Common Mistakes:

• Using ^ instead of ** for power
• Trying to use pow() like in other languages
• Typing invalid operators like ^^

3. What will be the output of the following code?

console.log(10 % 4);

medium

A. 6

B. 0

C. 2

D. 4

Solution

1. Step 1: Calculate 10 divided by 4

   10 divided by 4 is 2 with a remainder of 2.

2. Step 2: Understand the % operator

   The % operator returns the remainder, so 10 % 4 equals 2.

3. Final Answer:

   2 -> Option C

4. Quick Check:

   10 % 4 = 2 [OK]

Hint: Remainder is what's left after division [OK]

Common Mistakes:

• Confusing remainder with quotient
• Thinking % does division
• Choosing 0 or 4 as remainder incorrectly

4. Find the error in this code snippet:

let result = 5 **;
console.log(result);

medium

A. console.log syntax error

B. Using wrong operator for power

C. Variable name 'result' is invalid

D. Missing right operand for ** operator

Solution

1. Step 1: Check the power operator usage

   The power operator ** needs two operands, like 5 ** 2. Here, the right operand is missing.

2. Step 2: Verify other parts of the code

   The variable name and console.log syntax are correct, so no errors there.

3. Final Answer:

   Missing right operand for ** operator -> Option D

4. Quick Check:

   Power operator needs two numbers [OK]

Hint: Power operator needs number on both sides [OK]

Common Mistakes:

• Leaving out the second number after **
• Thinking variable names cause error here
• Assuming console.log is wrong

5. You want to split 100 candies equally among 6 kids and find how many candies remain undistributed. Which expression gives the number of leftover candies?

hard

A. 100 / 6

B. 100 % 6

C. 100 - 6

D. 100 ** 6

Solution

1. Step 1: Understand the problem

   We want the leftover candies after dividing 100 by 6, which means the remainder.

2. Step 2: Choose the correct operator

   The remainder operator % gives the leftover amount, so 100 % 6 is correct.

3. Final Answer:

   100 % 6 -> Option B

4. Quick Check:

   Leftover = total % number [OK]

Hint: Use % to find leftovers after division [OK]

Common Mistakes:

• Using / which gives quotient, not remainder
• Subtracting numbers directly instead of remainder
• Using power operator mistakenly