JavaScript Numbers and Strings – MCQs

What is the output of the following code?

let x = 10;

let y = "5";

console.log(x + y);

• 15

• 105

• 10 + 5

• Error

Which of the following methods converts a number to a string?

• toNumber()

• toText()

• toString()

• parseInt()

What will be the output?

console.log(Number("123"));

• "123"

• 123

• NaN

• undefined

What is the output of:

console.log(parseInt("12.34"));

• 12.34

• 12

• 13

• NaN

Which method converts a number into an exponential notation?

• toExponential()

• toPrecision()

• toFixed()

• toLocaleString()

What is the output of:

console.log(isNaN("Hello"));

• true

• false

• "Hello"

• NaN

What is the output of:

console.log((0.1 + 0.2).toFixed(2));

• 0.3

• "0.30"

• 0.30

• "0.3"

Which method returns NaN if the value cannot be converted into a number?

• parseInt()

• Number()

• toNumber()

• eval()

What is the result of:

console.log(Math.floor(4.7));

• 4.7

• 4

• 5

• NaN

What does Math.random() return?

• A random integer

• A random decimal between 0 and 1

• A random number between 1 and 10

• Always 0