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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 725 · 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.√38 to 1 decimal place? (a) 6.1 (b) 6.0 (c) 6.2 (d) 6.3
  2. 2.Best estimate of 2892 ÷ 52? (a) 5800 (b) 580 (c) 58
  3. 3.Best estimate of 1917 ÷ 26? (a) 640 (b) 6400 (c) 64
  4. 4.Best estimate of 2427 ÷ 42? (a) 61 (b) 610 (c) 6100
  5. 5.Best estimate of 3324 ÷ 76? (a) 42 (b) 4200 (c) 420
  6. 6.√79 to 1 decimal place? (a) 9.2 (b) 8.9 (c) 9.0 (d) 9.1
  7. 7.Best estimate of 1528 ÷ 26? (a) 5100 (b) 51 (c) 510
  8. 8.Best estimate of 969 ÷ 76? (a) 120 (b) 1200 (c) 12
  9. 9.Best estimate of 1900 ÷ 32? (a) 630 (b) 6300 (c) 63
  10. 10.Best estimate of 3473 ÷ 68? (a) 500 (b) 5000 (c) 50
  11. 11.√62 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 8.2
  12. 12.Best estimate of 5932 ÷ 78? (a) 7400 (b) 740 (c) 74
  13. 13.√41 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.4 (d) 6.3
  14. 14.√24 to 1 decimal place? (a) 4.9 (b) 5.2 (c) 5.0 (d) 5.1
  15. 15.Best estimate of 2180 ÷ 28? (a) 7300 (b) 730 (c) 73
  16. 16.Best estimate of 1825 ÷ 74? (a) 26 (b) 260 (c) 2600
  17. 17.Best estimate of 1565 ÷ 34? (a) 52 (b) 5200 (c) 520
  18. 18.Best estimate of 3645 ÷ 87? (a) 410 (b) 4100 (c) 41
  19. 19.Best estimate of 545 ÷ 36? (a) 1400 (b) 14 (c) 140
  20. 20.Best estimate of 1599 ÷ 23? (a) 80 (b) 800 (c) 8000
  21. 21.Best estimate of 5253 ÷ 72? (a) 7500 (b) 75 (c) 750
  22. 22.Best estimate of 2800 ÷ 49? (a) 560 (b) 5600 (c) 56
  23. 23.Best estimate of 1803 ÷ 36? (a) 45 (b) 4500 (c) 450
  24. 24.Best estimate of 3123 ÷ 49? (a) 6200 (b) 620 (c) 62
  25. 25.Best estimate of 2595 ÷ 33? (a) 870 (b) 8700 (c) 87
  26. 26.Best estimate of 2059 ÷ 27? (a) 690 (b) 69 (c) 6900
  27. 27.√67 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.2 (d) 8.3
  28. 28.√34 to 1 decimal place? (a) 5.6 (b) 5.9 (c) 5.7 (d) 5.8
  29. 29.Best estimate of 2792 ÷ 51? (a) 560 (b) 5600 (c) 56
  30. 30.√30 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.7 (d) 5.6
  31. 31.√61 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.8 (d) 8.0
  32. 32.√37 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 6.1 (d) 6.3
  33. 33.√89 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.5
  34. 34.Best estimate of 1427 ÷ 57? (a) 2400 (b) 24 (c) 240
  35. 35.Best estimate of 824 ÷ 33? (a) 27 (b) 270 (c) 2700
  36. 36.Best estimate of 2163 ÷ 47? (a) 4300 (b) 43 (c) 430
  37. 37.Best estimate of 5351 ÷ 76? (a) 67 (b) 6700 (c) 670
  38. 38.√74 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.7
  39. 39.Best estimate of 2440 ÷ 26? (a) 810 (b) 8100 (c) 81
  40. 40.√43 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.4 (d) 6.5

Answer key

  1. 6.2
  2. 58
  3. 64
  4. 61
  5. 42
  6. 8.9
  7. 51
  8. 12
  9. 63
  10. 50
  11. 7.9
  12. 74
  13. 6.4
  14. 4.9
  15. 73
  16. 26
  17. 52
  18. 41
  19. 14
  20. 80
  21. 75
  22. 56
  23. 45
  24. 62
  25. 87
  26. 69
  27. 8.2
  28. 5.8
  29. 56
  30. 5.5
  31. 7.8
  32. 6.1
  33. 9.4
  34. 24
  35. 27
  36. 43
  37. 67
  38. 8.6
  39. 81
  40. 6.6

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