Quizzes » Numbers (basic)

1. All numbers in JavaScript are doubles

How many bits do doubles have?

128

2. Number literals

const x = 0x10;

assert.equal(x, 10)

assert.equal(x, 15)

assert.equal(x, 16)

3. Number literals

const x = 0b10;

assert.equal(x, 1)

assert.equal(x, 2)

assert.equal(x, 10)

4. Number literals

const x = 4e2;

assert.equal(x, 8)

assert.equal(x, 40)

assert.equal(x, 400)

5. Number literals

const x = 4e-2;

assert.equal(x, 0.04)

assert.equal(x, 0.4)

assert.equal(x, 2)

6. Accessing properties

const x = 123.unknownProperty;

What happens?

assert.equal(x, undefined)

TypeError

SyntaxError

7. Prefix incrementation operator

let x = 0;
const result = [++x, x];

What happens?

assert.deepEqual(result, [0, 0])

assert.deepEqual(result, [1, 1])

assert.deepEqual(result, [0, 1])

assert.deepEqual(result, [1, 0])

8. Postfix incrementation operator

let x = 0;
const result = [x++, x];

What happens?

assert.deepEqual(result, [0, 0])

assert.deepEqual(result, [1, 1])

assert.deepEqual(result, [0, 1])

assert.deepEqual(result, [1, 0])

9. Converting to number

assert.equal(Number(undefined), 0)

assert.equal(Number(undefined), 1)

assert.equal(Number(undefined), NaN)

10. Converting to number

assert.equal(Number(null), 0)

assert.equal(Number(null), 1)

assert.equal(Number(null), NaN)

11. Converting to number

assert.equal(Number(false), 0)

assert.equal(Number(false), 1)

assert.equal(Number(false), NaN)

12. Converting to number

assert.equal(Number(1), 0)

assert.equal(Number(1), 1)

assert.equal(Number(1), NaN)

13. Converting to number

assert.equal(Number('1'), 0)

assert.equal(Number('1'), 1)

assert.equal(Number('1'), NaN)

14. Converting to number

assert.equal(Number(''), 0)

assert.equal(Number(''), 1)

assert.equal(Number(''), NaN)

15. Which of these expressions are `true`?

assert.ok(NaN === NaN)

assert.ok(typeof NaN === 'number')

assert.ok(Infinity === Infinity)

Correct answers: 0 out of 0

Quizzes » Numbers (basic)

1. All numbers in JavaScript are doubles

2. Number literals

3. Number literals

4. Number literals

5. Number literals

6. Accessing properties

7. Prefix incrementation operator

8. Postfix incrementation operator

9. Converting to number

10. Converting to number

11. Converting to number

12. Converting to number

13. Converting to number

14. Converting to number

15. Which of these expressions are true?

15. Which of these expressions are `true`?