GCSE Powers and roots Practice Questions

Free GCSE Powers and roots practice questions with full step-by-step worked solutions. Covers squares, cubes, square roots, cube roots. Practise exam-style problems and check your method.

squarescubessquare rootscube rootspowers of 2powers of 3
GCSE Foundation70 questionsStep-by-step solutions
Question 1
1 markeasy
Work out 77 squared, that is 727^2.
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Worked solution

  1. Recall what the power means

    727^2

    A power tells you how many times to multiply the base by itself, so this means 77 multiplied 22 times.

  2. Write it out in full

    72=7×77^2 = 7 \times 7

    Writing every factor out makes the repeated multiplication clear.

  3. Multiply the final factor

    7×7=497 \times 7 = 49

    Multiply 77 by the last 77, giving 4949.

Answer
4949
Question 2
1 markeasy
Work out 626^2. (A 66 by 66 dot grid is shown to help you picture the square number.)
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Worked solution

  1. Recall what the power means

    626^2

    A power tells you how many times to multiply the base by itself, so this means 66 multiplied 22 times.

  2. Write it out in full

    62=6×66^2 = 6 \times 6

    Writing every factor out makes the repeated multiplication clear.

  3. Multiply the final factor

    6×6=366 \times 6 = 36

    Multiply 66 by the last 66, giving 3636.

  4. Picture it as a square array

    62=6 rows×6 columns=366^2 = 6 \text{ rows} \times 6 \text{ columns} = 36

    A square number is the number of dots in a square grid; a 66 by 66 grid holds 3636 dots.

Answer
3636
Question 3
2 marksintermediate
Work out 11211^2.
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Worked solution

  1. Recall what the power means

    11211^2

    A power tells you how many times to multiply the base by itself, so this means 1111 multiplied 22 times.

  2. Write it out in full

    112=11×1111^2 = 11 \times 11

    Writing every factor out makes the repeated multiplication clear.

  3. Multiply the final factor

    11×11=12111 \times 11 = 121

    Multiply 1111 by the last 1111, giving 121121.

  4. List the powers as a check

    111=11, 112=12111^1=11,\ 11^2=121

    Listing each power in order confirms none were missed.

  5. State the final answer

    112=12111^2 = 121

    So the value of the power is 121121.

  6. Underline the final answer

    =121= 121

    Write the answer on its own line so it is clear and easy to mark.

Answer
121121
Question 4
3 markshard
From the list 1616, 2020, 2525, 3030, 3636, write down all the square numbers.
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Worked solution

  1. Recall square numbers

    1,4,9,16,25,36,49,1,4,9,16,25,36,49,\dots

    Square numbers come from squaring whole numbers.

  2. Test 1616

    42=164^2 = 16

    1616 is a square number.

  3. Test 2020

    42=16, 52=254^2=16,\ 5^2=25

    2020 is between 1616 and 2525, so not square.

  4. Test 2525

    52=255^2 = 25

    2525 is a square number.

  5. Test 3030

    52=25, 62=365^2=25,\ 6^2=36

    3030 is between 2525 and 3636, so not square.

  6. Test 3636

    62=366^2 = 36

    3636 is a square number.

  7. Collect the squares

    16, 25, 3616,\ 25,\ 36

    Gather the ones that passed.

  8. State the answer

    16,25,3616, 25, 36

    These are the square numbers in the list.

  9. Check

    42,52,624^2,5^2,6^2

    They are 424^2, 525^2 and 626^2 respectively.

  10. Underline the final answer

    =16,25,36= 16, 25, 36

    Write the answer on its own line so it is clear and easy to mark.

Answer
16,25,3616, 25, 36
Question 5
5 markschallenging
A square patio is made from 196196 identical square tiles arranged in a square. (a) How many tiles are along each side? (b) How many tiles lie on the border (edge) of the patio?
Show worked solution

Worked solution

  1. Link tiles to a square array

    side2=196\text{side}^2 = 196

    A square arrangement means side x side tiles.

  2. Find the side

    side=196\text{side} = \sqrt{196}

    Take the square root of 196196.

  3. Try a number just below

    132=16913^2 = 169

    Testing 1313 gives 169169, which is too small.

  4. Try the next number

    142=19614^2 = 196

    Testing 1414 gives exactly 196196, so this is the root.

  5. Verify by multiplying back

    14×14=19614 \times 14 = 196

    Check the root by squaring it back to 196196.

  6. Split the second number by place value

    14×14=14×10+14×414 \times 14 = 14 \times 10 + 14 \times 4

    Break 1414 into 10+410 + 4 so we can multiply in easy parts.

  7. Multiply the tens part

    14×10=14014 \times 10 = 140

    First multiply by the 1010.

  8. Multiply the units part

    14×4=5614 \times 4 = 56

    Then multiply by the 44.

  9. Add the two parts

    140+56=196140 + 56 = 196

    Add the partial products to get 196196.

  10. State part (a)

    14 tiles per side14 \text{ tiles per side}

    Each side has 1414 tiles.

  11. Set up the border count

    4×144 \times 14

    Four sides of 1414 tiles each is a first estimate.

  12. Multiply

    4×14=564 \times 14 = 56

    That gives 5656.

  13. Adjust for corners

    564=5256 - 4 = 52

    The 44 corner tiles were counted twice, so subtract 44.

  14. State part (b)

    52 border tiles52 \text{ border tiles}

    There are 5252 tiles on the border.

  15. Sense check

    142122=196144=5214^2 - 12^2 = 196 - 144 = 52

    Total tiles minus the 1212x122 interior also gives 5252 border tiles.

  16. Final answer

    5252

    The requested final answer is the border count, 5252.

Answer
5252

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