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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 288 · 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 4568 ÷ 78? (a) 570 (b) 57 (c) 5700
  2. 2.Best estimate of 5933 ÷ 81? (a) 74 (b) 740 (c) 7400
  3. 3.Best estimate of 2332 ÷ 48? (a) 470 (b) 4700 (c) 47
  4. 4.Best estimate of 2652 ÷ 33? (a) 880 (b) 8800 (c) 88
  5. 5.√66 to 1 decimal place? (a) 8.0 (b) 7.8 (c) 7.9 (d) 8.1
  6. 6.Best estimate of 1126 ÷ 89? (a) 1300 (b) 130 (c) 13
  7. 7.Best estimate of 4147 ÷ 76? (a) 520 (b) 5200 (c) 52
  8. 8.√34 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.8
  9. 9.Best estimate of 3466 ÷ 81? (a) 430 (b) 4300 (c) 43
  10. 10.Best estimate of 3574 ÷ 69? (a) 51 (b) 510 (c) 5100
  11. 11.√26 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.2 (d) 5.0
  12. 12.√65 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 8.1 (d) 8.0
  13. 13.Best estimate of 4807 ÷ 77? (a) 600 (b) 6000 (c) 60
  14. 14.Best estimate of 2315 ÷ 29? (a) 77 (b) 770 (c) 7700
  15. 15.Best estimate of 964 ÷ 22? (a) 48 (b) 4800 (c) 480
  16. 16.√94 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.8 (d) 9.7
  17. 17.Best estimate of 1577 ÷ 26? (a) 530 (b) 5300 (c) 53
  18. 18.√70 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.4 (d) 8.7
  19. 19.Best estimate of 4348 ÷ 62? (a) 720 (b) 72 (c) 7200
  20. 20.Best estimate of 2567 ÷ 29? (a) 860 (b) 8600 (c) 86
  21. 21.√52 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.2 (d) 7.1
  22. 22.√74 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.6 (d) 8.5
  23. 23.Best estimate of 3472 ÷ 56? (a) 5800 (b) 580 (c) 58
  24. 24.√89 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.2 (d) 9.1
  25. 25.Best estimate of 704 ÷ 38? (a) 1800 (b) 18 (c) 180
  26. 26.Best estimate of 3573 ÷ 39? (a) 890 (b) 8900 (c) 89
  27. 27.√92 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 9.6
  28. 28.√96 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 10.0 (d) 9.7
  29. 29.Best estimate of 2585 ÷ 41? (a) 65 (b) 650 (c) 6500
  30. 30.Best estimate of 1008 ÷ 44? (a) 250 (b) 2500 (c) 25
  31. 31.√45 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  32. 32.Best estimate of 2950 ÷ 31? (a) 980 (b) 98 (c) 9800
  33. 33.√80 to 1 decimal place? (a) 8.9 (b) 9.2 (c) 9.0 (d) 9.1
  34. 34.√55 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.4
  35. 35.√79 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 9.0 (d) 8.9
  36. 36.Best estimate of 1445 ÷ 76? (a) 18 (b) 1800 (c) 180
  37. 37.Best estimate of 1293 ÷ 63? (a) 22 (b) 2200 (c) 220
  38. 38.√61 to 1 decimal place? (a) 7.8 (b) 7.5 (c) 7.7 (d) 7.6
  39. 39.√63 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.9 (d) 7.7
  40. 40.Best estimate of 807 ÷ 27? (a) 2700 (b) 270 (c) 27

Answer key

  1. 57
  2. 74
  3. 47
  4. 88
  5. 8.1
  6. 13
  7. 52
  8. 5.8
  9. 43
  10. 51
  11. 5.1
  12. 8.1
  13. 60
  14. 77
  15. 48
  16. 9.7
  17. 53
  18. 8.4
  19. 72
  20. 86
  21. 7.2
  22. 8.6
  23. 58
  24. 9.4
  25. 18
  26. 89
  27. 9.6
  28. 9.8
  29. 65
  30. 25
  31. 6.7
  32. 98
  33. 8.9
  34. 7.4
  35. 8.9
  36. 18
  37. 22
  38. 7.8
  39. 7.9
  40. 27

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