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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 554 · 40 questions
TalentJR

How to do it in your head (Guess, divide, average): Division: round the divisor to the nearest ten and find the closest multiple of it. Square root: guess the nearest whole root, then divide the number by your guess. Average the guess and the answer of the division, and round to 1 decimal place.

NameDateTime takenScore ___ / 40
  1. 1.Best estimate of 2519 ÷ 62? (a) 420 (b) 42 (c) 4200
  2. 2.√34 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 5.7
  3. 3.√96 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.6 (d) 9.5
  4. 4.Best estimate of 6232 ÷ 67? (a) 8900 (b) 89 (c) 890
  5. 5.√35 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 6.2 (d) 6.1
  6. 6.Best estimate of 1119 ÷ 38? (a) 2800 (b) 280 (c) 28
  7. 7.√92 to 1 decimal place? (a) 9.4 (b) 9.7 (c) 9.5 (d) 9.6
  8. 8.√69 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.6 (d) 8.4
  9. 9.√53 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.2 (d) 7.3
  10. 10.Best estimate of 2263 ÷ 33? (a) 750 (b) 75 (c) 7500
  11. 11.Best estimate of 5958 ÷ 66? (a) 8500 (b) 850 (c) 85
  12. 12.Best estimate of 1561 ÷ 21? (a) 7800 (b) 78 (c) 780
  13. 13.Best estimate of 1396 ÷ 36? (a) 350 (b) 3500 (c) 35
  14. 14.Best estimate of 2472 ÷ 42? (a) 620 (b) 6200 (c) 62
  15. 15.Best estimate of 3537 ÷ 73? (a) 5100 (b) 510 (c) 51
  16. 16.Best estimate of 707 ÷ 52? (a) 140 (b) 14 (c) 1400
  17. 17.√71 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.3 (d) 8.4
  18. 18.√77 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.8 (d) 8.7
  19. 19.√20 to 1 decimal place? (a) 4.3 (b) 4.6 (c) 4.4 (d) 4.5
  20. 20.Best estimate of 3389 ÷ 76? (a) 420 (b) 4200 (c) 42
  21. 21.Best estimate of 2094 ÷ 54? (a) 4200 (b) 420 (c) 42
  22. 22.Best estimate of 1313 ÷ 78? (a) 1600 (b) 16 (c) 160
  23. 23.√58 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.5 (d) 7.8
  24. 24.√52 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 7.3
  25. 25.√37 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.2 (d) 6.1
  26. 26.Best estimate of 3429 ÷ 72? (a) 490 (b) 4900 (c) 49
  27. 27.Best estimate of 5589 ÷ 87? (a) 620 (b) 6200 (c) 62
  28. 28.Best estimate of 997 ÷ 47? (a) 2000 (b) 20 (c) 200
  29. 29.Best estimate of 998 ÷ 79? (a) 12 (b) 120 (c) 1200
  30. 30.√43 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.7 (d) 6.4
  31. 31.Best estimate of 2530 ÷ 27? (a) 840 (b) 84 (c) 8400
  32. 32.√67 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.9 (d) 8.2
  33. 33.Best estimate of 4882 ÷ 72? (a) 7000 (b) 70 (c) 700
  34. 34.Best estimate of 3169 ÷ 56? (a) 53 (b) 5300 (c) 530
  35. 35.Best estimate of 1250 ÷ 42? (a) 31 (b) 3100 (c) 310
  36. 36.√84 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 8.9 (d) 9.0
  37. 37.√65 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 8.2 (d) 7.9
  38. 38.√61 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 8.1 (d) 7.9
  39. 39.√21 to 1 decimal place? (a) 4.3 (b) 4.5 (c) 4.6 (d) 4.4
  40. 40.√48 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 7.1 (d) 7.0

Answer key

  1. 42
  2. 5.8
  3. 9.8
  4. 89
  5. 5.9
  6. 28
  7. 9.6
  8. 8.3
  9. 7.3
  10. 75
  11. 85
  12. 78
  13. 35
  14. 62
  15. 51
  16. 14
  17. 8.4
  18. 8.8
  19. 4.5
  20. 42
  21. 42
  22. 16
  23. 7.6
  24. 7.2
  25. 6.1
  26. 49
  27. 62
  28. 20
  29. 12
  30. 6.6
  31. 84
  32. 8.2
  33. 70
  34. 53
  35. 31
  36. 9.2
  37. 8.1
  38. 7.8
  39. 4.6
  40. 6.9

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