Top Practice Questions to Enhance Your Skills

Practice Questions

1. What is the value of age after this code runs?

Code Example:

let age = 10;
age + 2;  // ❎ This does nothing since the result is not stored.
age = age + 2;  // ✅ Correct way to update the value of 'age'

In JavaScript, the = sign is known as the assignment operator. Its purpose is to take the value on the right-hand side of the equation and store it in the variable on the left-hand side.

After the code executes:

• The value of age becomes 12 because age = age + 2 assigns the new calculated value back to age.

Explanation:

The first statement age + 2; does not modify age because the result is not assigned to a variable. Only the second statement updates the value of age.

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2. What is the value of avg after this code runs?

Code Example:

let num1 = 10;
let num2 = 20;
let avg = (num1 + num2) / 2;

Explanation:

• The avg variable calculates the average of num1 and num2.

• First, the sum of num1 and num2 is calculated: 10 + 20 = 30.

• Then, the result is divided by 2: 30 / 2 = 15.

So, the value of avg is 15.

Key Points:

1. Parentheses () ensure the addition operation is performed before division, following the operator precedence rules.

2. Always remember to use proper grouping when working with complex calculations.

Program Output:

console.log(avg);  // Output: 15