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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 888 · 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 2225 ÷ 66? (a) 3200 (b) 320 (c) 32
  2. 2.Best estimate of 1685 ÷ 21? (a) 8400 (b) 84 (c) 840
  3. 3.Best estimate of 2902 ÷ 37? (a) 730 (b) 7300 (c) 73
  4. 4.√96 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  5. 5.√55 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.2 (d) 7.3
  6. 6.Best estimate of 932 ÷ 34? (a) 310 (b) 31 (c) 3100
  7. 7.Best estimate of 2065 ÷ 34? (a) 6900 (b) 690 (c) 69
  8. 8.Best estimate of 2393 ÷ 54? (a) 4800 (b) 48 (c) 480
  9. 9.Best estimate of 1241 ÷ 32? (a) 4100 (b) 41 (c) 410
  10. 10.√45 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 7.0
  11. 11.Best estimate of 2977 ÷ 32? (a) 99 (b) 9900 (c) 990
  12. 12.Best estimate of 3337 ÷ 83? (a) 42 (b) 420 (c) 4200
  13. 13.Best estimate of 1725 ÷ 36? (a) 430 (b) 4300 (c) 43
  14. 14.√28 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.2 (d) 5.0
  15. 15.Best estimate of 645 ÷ 32? (a) 2200 (b) 22 (c) 220
  16. 16.Best estimate of 1188 ÷ 52? (a) 2400 (b) 240 (c) 24
  17. 17.√61 to 1 decimal place? (a) 7.5 (b) 7.8 (c) 7.6 (d) 7.7
  18. 18.Best estimate of 1500 ÷ 31? (a) 500 (b) 50 (c) 5000
  19. 19.√76 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  20. 20.Best estimate of 2812 ÷ 32? (a) 940 (b) 94 (c) 9400
  21. 21.√40 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.0 (d) 6.1
  22. 22.Best estimate of 1321 ÷ 58? (a) 2200 (b) 220 (c) 22
  23. 23.√26 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.4 (d) 5.2
  24. 24.Best estimate of 2598 ÷ 56? (a) 43 (b) 430 (c) 4300
  25. 25.√37 to 1 decimal place? (a) 6.0 (b) 6.2 (c) 6.1 (d) 5.9
  26. 26.Best estimate of 1448 ÷ 78? (a) 18 (b) 180 (c) 1800
  27. 27.√50 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 7.0 (d) 7.2
  28. 28.Best estimate of 1472 ÷ 46? (a) 2900 (b) 29 (c) 290
  29. 29.Best estimate of 5075 ÷ 56? (a) 8500 (b) 85 (c) 850
  30. 30.Best estimate of 1314 ÷ 76? (a) 160 (b) 1600 (c) 16
  31. 31.√94 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.6 (d) 9.8
  32. 32.Best estimate of 2122 ÷ 79? (a) 270 (b) 27 (c) 2700
  33. 33.Best estimate of 713 ÷ 43? (a) 1800 (b) 18 (c) 180
  34. 34.Best estimate of 2137 ÷ 39? (a) 530 (b) 5300 (c) 53
  35. 35.Best estimate of 4069 ÷ 59? (a) 68 (b) 680 (c) 6800
  36. 36.Best estimate of 2765 ÷ 47? (a) 550 (b) 55 (c) 5500
  37. 37.Best estimate of 2531 ÷ 62? (a) 42 (b) 420 (c) 4200
  38. 38.√34 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.8 (d) 5.7
  39. 39.√56 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.3 (d) 7.5
  40. 40.√22 to 1 decimal place? (a) 4.5 (b) 4.8 (c) 4.7 (d) 4.6

Answer key

  1. 32
  2. 84
  3. 73
  4. 9.8
  5. 7.4
  6. 31
  7. 69
  8. 48
  9. 41
  10. 6.7
  11. 99
  12. 42
  13. 43
  14. 5.3
  15. 22
  16. 24
  17. 7.8
  18. 50
  19. 8.7
  20. 94
  21. 6.3
  22. 22
  23. 5.1
  24. 43
  25. 6.1
  26. 18
  27. 7.1
  28. 29
  29. 85
  30. 16
  31. 9.7
  32. 27
  33. 18
  34. 53
  35. 68
  36. 55
  37. 42
  38. 5.8
  39. 7.5
  40. 4.7

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