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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 945 · 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 713 ÷ 51? (a) 1400 (b) 140 (c) 14
  2. 2.Best estimate of 348 ÷ 28? (a) 1200 (b) 120 (c) 12
  3. 3.Best estimate of 1551 ÷ 51? (a) 31 (b) 3100 (c) 310
  4. 4.√98 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.9
  5. 5.√32 to 1 decimal place? (a) 5.6 (b) 5.8 (c) 5.7 (d) 5.5
  6. 6.√45 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.9 (d) 6.6
  7. 7.Best estimate of 3654 ÷ 52? (a) 7300 (b) 730 (c) 73
  8. 8.√56 to 1 decimal place? (a) 7.8 (b) 7.5 (c) 7.6 (d) 7.7
  9. 9.√27 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.2 (d) 5.5
  10. 10.√40 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.3 (d) 6.2
  11. 11.Best estimate of 1978 ÷ 56? (a) 330 (b) 3300 (c) 33
  12. 12.√83 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.0
  13. 13.Best estimate of 1055 ÷ 79? (a) 130 (b) 1300 (c) 13
  14. 14.Best estimate of 5308 ÷ 66? (a) 76 (b) 7600 (c) 760
  15. 15.Best estimate of 3008 ÷ 46? (a) 6000 (b) 60 (c) 600
  16. 16.Best estimate of 4496 ÷ 62? (a) 750 (b) 7500 (c) 75
  17. 17.Best estimate of 1726 ÷ 56? (a) 290 (b) 2900 (c) 29
  18. 18.Best estimate of 692 ÷ 33? (a) 2300 (b) 23 (c) 230
  19. 19.√47 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 7.2 (d) 7.0
  20. 20.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.5 (d) 9.6
  21. 21.Best estimate of 1208 ÷ 32? (a) 400 (b) 4000 (c) 40
  22. 22.Best estimate of 573 ÷ 46? (a) 11 (b) 110 (c) 1100
  23. 23.√92 to 1 decimal place? (a) 9.7 (b) 9.5 (c) 9.6 (d) 9.8
  24. 24.√65 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.4
  25. 25.Best estimate of 1627 ÷ 34? (a) 54 (b) 540 (c) 5400
  26. 26.√51 to 1 decimal place? (a) 7.3 (b) 7.2 (c) 7.0 (d) 7.1
  27. 27.Best estimate of 965 ÷ 36? (a) 24 (b) 2400 (c) 240
  28. 28.√59 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.8 (d) 7.5
  29. 29.√67 to 1 decimal place? (a) 8.2 (b) 8.4 (c) 8.3 (d) 8.1
  30. 30.√63 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.8 (d) 8.0
  31. 31.Best estimate of 7499 ÷ 81? (a) 9400 (b) 94 (c) 940
  32. 32.Best estimate of 2051 ÷ 76? (a) 260 (b) 26 (c) 2600
  33. 33.Best estimate of 4141 ÷ 66? (a) 590 (b) 59 (c) 5900
  34. 34.√31 to 1 decimal place? (a) 5.7 (b) 5.5 (c) 5.6 (d) 5.8
  35. 35.Best estimate of 1120 ÷ 72? (a) 160 (b) 1600 (c) 16
  36. 36.Best estimate of 4105 ÷ 89? (a) 46 (b) 460 (c) 4600
  37. 37.Best estimate of 1069 ÷ 33? (a) 36 (b) 360 (c) 3600
  38. 38.Best estimate of 3071 ÷ 58? (a) 510 (b) 51 (c) 5100
  39. 39.Best estimate of 2987 ÷ 67? (a) 4300 (b) 430 (c) 43
  40. 40.√66 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2

Answer key

  1. 14
  2. 12
  3. 31
  4. 9.9
  5. 5.7
  6. 6.7
  7. 73
  8. 7.5
  9. 5.2
  10. 6.3
  11. 33
  12. 9.1
  13. 13
  14. 76
  15. 60
  16. 75
  17. 29
  18. 23
  19. 6.9
  20. 9.7
  21. 40
  22. 11
  23. 9.6
  24. 8.1
  25. 54
  26. 7.1
  27. 24
  28. 7.7
  29. 8.2
  30. 7.9
  31. 94
  32. 26
  33. 59
  34. 5.6
  35. 16
  36. 46
  37. 36
  38. 51
  39. 43
  40. 8.1

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