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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 964 · 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 2586 ÷ 57? (a) 4300 (b) 43 (c) 430
  2. 2.Best estimate of 1257 ÷ 43? (a) 3100 (b) 310 (c) 31
  3. 3.√98 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.8 (d) 9.9
  4. 4.Best estimate of 5384 ÷ 84? (a) 6700 (b) 670 (c) 67
  5. 5.Best estimate of 1785 ÷ 58? (a) 300 (b) 30 (c) 3000
  6. 6.√80 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.7 (d) 8.9
  7. 7.Best estimate of 3280 ÷ 76? (a) 4100 (b) 41 (c) 410
  8. 8.√85 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.4 (d) 9.3
  9. 9.Best estimate of 1114 ÷ 56? (a) 1900 (b) 190 (c) 19
  10. 10.Best estimate of 4723 ÷ 61? (a) 7900 (b) 79 (c) 790
  11. 11.√48 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 7.2 (d) 7.0
  12. 12.Best estimate of 3968 ÷ 88? (a) 4400 (b) 440 (c) 44
  13. 13.Best estimate of 2397 ÷ 46? (a) 48 (b) 4800 (c) 480
  14. 14.Best estimate of 3636 ÷ 62? (a) 610 (b) 6100 (c) 61
  15. 15.Best estimate of 5247 ÷ 86? (a) 580 (b) 5800 (c) 58
  16. 16.√61 to 1 decimal place? (a) 8.1 (b) 7.9 (c) 8.0 (d) 7.8
  17. 17.Best estimate of 6096 ÷ 87? (a) 6800 (b) 68 (c) 680
  18. 18.√53 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.3 (d) 7.6
  19. 19.Best estimate of 352 ÷ 28? (a) 1200 (b) 120 (c) 12
  20. 20.Best estimate of 4059 ÷ 58? (a) 68 (b) 6800 (c) 680
  21. 21.Best estimate of 4603 ÷ 66? (a) 6600 (b) 66 (c) 660
  22. 22.√21 to 1 decimal place? (a) 4.7 (b) 4.5 (c) 4.4 (d) 4.6
  23. 23.Best estimate of 2954 ÷ 34? (a) 980 (b) 9800 (c) 98
  24. 24.Best estimate of 2023 ÷ 62? (a) 3400 (b) 34 (c) 340
  25. 25.Best estimate of 2477 ÷ 42? (a) 620 (b) 6200 (c) 62
  26. 26.Best estimate of 4037 ÷ 86? (a) 45 (b) 450 (c) 4500
  27. 27.√86 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.5 (d) 9.4
  28. 28.√87 to 1 decimal place? (a) 9.1 (b) 9.4 (c) 9.3 (d) 9.2
  29. 29.Best estimate of 3196 ÷ 46? (a) 64 (b) 6400 (c) 640
  30. 30.Best estimate of 1033 ÷ 31? (a) 340 (b) 3400 (c) 34
  31. 31.Best estimate of 2282 ÷ 29? (a) 760 (b) 7600 (c) 76
  32. 32.√46 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.6 (d) 6.8
  33. 33.Best estimate of 3088 ÷ 46? (a) 62 (b) 6200 (c) 620
  34. 34.Best estimate of 2024 ÷ 56? (a) 3400 (b) 34 (c) 340
  35. 35.Best estimate of 5285 ÷ 81? (a) 66 (b) 6600 (c) 660
  36. 36.Best estimate of 3061 ÷ 76? (a) 3800 (b) 38 (c) 380
  37. 37.Best estimate of 3523 ÷ 54? (a) 70 (b) 7000 (c) 700
  38. 38.√29 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.2 (d) 5.4
  39. 39.√44 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.4 (d) 6.6
  40. 40.Best estimate of 4075 ÷ 46? (a) 8200 (b) 82 (c) 820

Answer key

  1. 43
  2. 31
  3. 9.9
  4. 67
  5. 30
  6. 8.9
  7. 41
  8. 9.2
  9. 19
  10. 79
  11. 6.9
  12. 44
  13. 48
  14. 61
  15. 58
  16. 7.8
  17. 68
  18. 7.3
  19. 12
  20. 68
  21. 66
  22. 4.6
  23. 98
  24. 34
  25. 62
  26. 45
  27. 9.3
  28. 9.3
  29. 64
  30. 34
  31. 76
  32. 6.8
  33. 62
  34. 34
  35. 66
  36. 38
  37. 70
  38. 5.4
  39. 6.6
  40. 82

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