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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 838 · 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 740 ÷ 22? (a) 37 (b) 3700 (c) 370
  2. 2.√20 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.6 (d) 4.5
  3. 3.Best estimate of 908 ÷ 31? (a) 3000 (b) 300 (c) 30
  4. 4.√62 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.8 (d) 7.9
  5. 5.Best estimate of 697 ÷ 36? (a) 170 (b) 17 (c) 1700
  6. 6.Best estimate of 3169 ÷ 62? (a) 53 (b) 530 (c) 5300
  7. 7.Best estimate of 2316 ÷ 73? (a) 330 (b) 3300 (c) 33
  8. 8.Best estimate of 5918 ÷ 64? (a) 990 (b) 99 (c) 9900
  9. 9.√90 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.5
  10. 10.Best estimate of 1652 ÷ 72? (a) 2400 (b) 240 (c) 24
  11. 11.Best estimate of 1474 ÷ 28? (a) 490 (b) 49 (c) 4900
  12. 12.√51 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.0 (d) 7.1
  13. 13.Best estimate of 1149 ÷ 63? (a) 1900 (b) 190 (c) 19
  14. 14.√41 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.1 (d) 6.2
  15. 15.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  16. 16.√74 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  17. 17.Best estimate of 2176 ÷ 81? (a) 270 (b) 2700 (c) 27
  18. 18.Best estimate of 4600 ÷ 76? (a) 580 (b) 5800 (c) 58
  19. 19.Best estimate of 968 ÷ 56? (a) 1600 (b) 160 (c) 16
  20. 20.√23 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 5.1 (d) 4.8
  21. 21.Best estimate of 3512 ÷ 66? (a) 500 (b) 5000 (c) 50
  22. 22.Best estimate of 4887 ÷ 52? (a) 98 (b) 9800 (c) 980
  23. 23.√44 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.8 (d) 6.7
  24. 24.√80 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.2 (d) 9.1
  25. 25.Best estimate of 4749 ÷ 86? (a) 53 (b) 530 (c) 5300
  26. 26.Best estimate of 4630 ÷ 71? (a) 66 (b) 660 (c) 6600
  27. 27.Best estimate of 2068 ÷ 54? (a) 41 (b) 4100 (c) 410
  28. 28.√69 to 1 decimal place? (a) 8.3 (b) 8.0 (c) 8.1 (d) 8.2
  29. 29.√94 to 1 decimal place? (a) 9.8 (b) 10.0 (c) 9.7 (d) 9.9
  30. 30.Best estimate of 2886 ÷ 82? (a) 36 (b) 360 (c) 3600
  31. 31.√89 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.7 (d) 9.6
  32. 32.Best estimate of 4065 ÷ 63? (a) 68 (b) 680 (c) 6800
  33. 33.Best estimate of 2207 ÷ 71? (a) 3200 (b) 320 (c) 32
  34. 34.√29 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.2 (d) 5.4
  35. 35.√96 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.8 (d) 9.9
  36. 36.√31 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.8
  37. 37.Best estimate of 3583 ÷ 51? (a) 7200 (b) 720 (c) 72
  38. 38.√84 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.2 (d) 9.4
  39. 39.Best estimate of 8009 ÷ 87? (a) 890 (b) 8900 (c) 89
  40. 40.Best estimate of 2356 ÷ 31? (a) 7900 (b) 790 (c) 79

Answer key

  1. 37
  2. 4.5
  3. 30
  4. 7.9
  5. 17
  6. 53
  7. 33
  8. 99
  9. 9.5
  10. 24
  11. 49
  12. 7.1
  13. 19
  14. 6.4
  15. 6.3
  16. 8.6
  17. 27
  18. 58
  19. 16
  20. 4.8
  21. 50
  22. 98
  23. 6.6
  24. 8.9
  25. 53
  26. 66
  27. 41
  28. 8.3
  29. 9.7
  30. 36
  31. 9.4
  32. 68
  33. 32
  34. 5.4
  35. 9.8
  36. 5.6
  37. 72
  38. 9.2
  39. 89
  40. 79

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