Number type behavior in Typescript - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

Output of arithmetic with mixed number types

What is the output of this TypeScript code snippet?

Typescript

const a: number = 5;
const b: number = 2.5;
const c = a + b;
console.log(c);

A 7

B 7.5

C TypeError

D NaN

💡 Hint

Remember that TypeScript's number type includes both integers and decimals.

In TypeScript, the number type covers all numeric values including decimals. Adding 5 and 2.5 results in 7.5.

❓ Predict Output

intermediate

Result of dividing by zero

What will this TypeScript code output?

Typescript

const x = 10 / 0;
console.log(x);

A Infinity

B NaN

C 0

D Throws an error

💡 Hint

Think about how JavaScript and TypeScript handle division by zero.

Dividing a positive number by zero in TypeScript results in Infinity, not an error.

❓ Predict Output

advanced

Output of bitwise operation on numbers

What is the output of this code?

Typescript

const a = 5; // binary 0101
const b = 3; // binary 0011
const c = a & b;
console.log(c);

A 8

B 7

C 1

D TypeError

💡 Hint

Bitwise AND compares each bit of the numbers.

5 in binary is 0101, 3 is 0011. Bitwise AND is 0001 which is 1 in decimal.

❓ Predict Output

advanced

Behavior of Number.MAX_SAFE_INTEGER + 1

What is the output of this TypeScript code?

Typescript

console.log(Number.MAX_SAFE_INTEGER + 1 === Number.MAX_SAFE_INTEGER + 2);

A undefined

B false

C Throws an error

D true

💡 Hint

Consider the precision limits of JavaScript numbers.

Numbers beyond MAX_SAFE_INTEGER lose precision, so adding 1 or 2 results in the same value.

❓ Predict Output

expert

Output of floating point addition precision

What is the output of this code snippet?

Typescript

const a = 0.1 + 0.2;
console.log(a === 0.3);

A false

B true

C TypeError

D NaN

💡 Hint

Think about how floating point numbers are stored in computers.

Due to floating point precision errors, 0.1 + 0.2 is not exactly 0.3, so the comparison is false.