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Binary numbers – practice for Years 6–8

Sample questions on Binary numbers with the right answer and a worked solution, from easy to hard. In the Pickles Academy app a child gets new questions of the same kind every time, so they can't just learn the answers by heart.

Subject
Computing
Year
Years 6–8
Curriculum area
Data, information and modelling

Question types: Binary and bits

Rule: Binary numbers

Binary place values are 1, 2, 4, 8, 16, 32, 64, 128 (from right to left). A bit is 0 or 1, a byte is 8 bits.

To convert, take the biggest power of 2 that fits, write 1 and subtract it; where it doesn’t fit, write 0.

Example: 13 = 8 + 4 + 1 → 1101

Watch out: Don’t leave out the zeros in the middle: 9 = 8 + 1 is 1001, not 11.

Sample questions

  1. Question 1 Easy

    Convert the binary number 1010 to a decimal number.

    Show the solution
    Answer: 10

    How it works: 1 × 8 + 0 × 4 + 1 × 2 + 0 × 1 = 10

  2. Question 2 Normal

    Write 61 as a binary number (only zeros and ones).

    Show the solution
    Answer: 111101

    How it works: 61 = 32 + 16 + 8 + 4 + 1 → 111101

  3. Question 3 Hard

    How many different numbers can be written with 7 bits?

    Show the solution
    Answer: 128

    How it works: Each bit has 2 values: 2^7 = 128.

Related topics

All Computing topics

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