Lesson 4.5.4.2

4.5.4.2 Unsigned binary arithmetic Quiz: AQA Computer Science, Unit 5

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.5.4.2, Unsigned binary arithmetic: 20 multiple choice questions for the AQA Computer Science (7517), Unit 5: Fundamentals of data representation, written with Revision Ninja.

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The 20 questions

  1. What is 1 + 1 in binary, with the carry?

    • 100
    • 01
    • 10
    • 11

  2. What is 1 + 1 + 1 in binary?

    • 10
    • 11
    • 111
    • 100

  3. When adding two binary digits 1 and 1, what is written in that column and what is carried?

    • 1 is written and 2 is carried
    • 0 is written and 0 is carried
    • 0 is written and 1 is carried
    • 1 is written and 0 is carried

  4. What is 1 x 1 in binary?

    • 11
    • 1
    • 0
    • 10

  5. In binary long multiplication, what is the partial product when the multiplier bit is 0?

    • The multiplicand unchanged
    • All zeros, shifted into position
    • The multiplier shifted left
    • A carry of 1

  6. What does a carry out of the most significant bit indicate in unsigned addition?

    • The two operands were equal
    • The result is exact and no overflow occurred
    • The result is negative
    • The true sum needs one more bit than the operands had

  7. What does shifting an unsigned binary number one place to the left do?

    • Divides it by 2
    • Multiplies it by 10
    • Multiplies it by 2
    • Adds 1 to it

  8. Add the unsigned 4-bit binary numbers 1011 and 0110. What is the result?

    • 0001 with a carry out, which is 10001 in five bits
    • 0111 with a carry out, because the carry bit is added back into the lower four bits
    • 1001 with no carry, because the sum is reduced modulo 8 when the carry is discarded
    • 1111 with no carry, since the sum of the two inputs stays within the 4-bit range

  9. Add the unsigned 4-bit binary numbers 1101 and 0011. What is the result?

    • 1100 with a carry out
    • 1111 with no carry
    • 0000 with a carry out
    • 0001 with no carry

  10. Add the unsigned 4-bit binary numbers 1010 and 0101. What is the result?

    • 0111 with no carry
    • 0000 with a carry out
    • 1111 with no carry
    • 1110 with a carry out

  11. Multiply the unsigned binary number 1011 by 10. What is the result?

    • 10110
    • 10101
    • 11011
    • 10011

  12. Multiply the unsigned binary numbers 1011 and 1011. What is the result?

    • 1111011
    • 1111001
    • 1110001
    • 1101001

  13. Multiply the unsigned binary numbers 110 and 101. What is the result?

    • 10110
    • 11110
    • 11010
    • 11100

  14. Add the unsigned 8-bit binary numbers 0111 1111 and 0000 0001. What is the result?

    • 1000 0000
    • 0111 1110
    • 1111 1111
    • 1000 0001

  15. Add the unsigned 8-bit binary numbers 1111 1111 and 0000 0001. What is the result?

    • 1111 1111 with no carry, since the adder keeps the largest value it can hold
    • 0000 0000 with a carry out, so the sum overflows 8 bits
    • 1000 0000 with no carry, because the sum is halved when the carry is removed
    • 0000 0001 with a carry out, since only the lowest bit of the sum is ever kept

  16. Multiply the unsigned binary numbers 1101 and 101. What is the result?

    • 0111001
    • 1010001
    • 1000001
    • 1001001

  17. Why might the product of two unsigned n-bit numbers need up to 2n bits to store?

    • Each bit of the multiplier doubles the number of bits used, so the product grows with every set bit
    • The product always has exactly n + 1 bits, because one extra bit is needed for every multiplication step
    • The largest product, (2^n - 1)^2, is below 2^(2n), so it can need up to 2n bits
    • Products are always stored with a separate sign bit, which adds one bit to the full width

  18. Why does binary multiplication work as shift and add?

    • Each 1 bit in the multiplier contributes a shifted copy of the multiplicand, and the copies are summed
    • Shifted copies of the multiplier are averaged together, which gives the product of the two values
    • Each 0 bit in the multiplier doubles the multiplicand, so the copies grow with every zero bit
    • Multiplication is carried out by repeated subtraction of the multiplicand from the multiplier value

  19. What is the binary number 1011 (decimal 11) shifted left by two places?

    • 1011100
    • 101000
    • 101100
    • 10110

  20. Add 200 and 100 as 8-bit unsigned numbers. Which statement is correct?

    • The result is 0000 0000 with no carry, since sums wrap silently
    • The result is 0100 1100 with no carry, since 300 fits in 8 bits
    • The result is 1100 1000 with no carry, since 200 is the larger operand
    • The 8-bit result is 0010 1100 with a carry out, so the true sum of 300 does not fit

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