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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 496 · 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.√75 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.6 (d) 8.8
  2. 2.√44 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.5 (d) 6.7
  3. 3.√80 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 8.9
  4. 4.Best estimate of 1361 ÷ 58? (a) 230 (b) 2300 (c) 23
  5. 5.Best estimate of 4672 ÷ 83? (a) 5800 (b) 580 (c) 58
  6. 6.Best estimate of 5131 ÷ 66? (a) 7300 (b) 73 (c) 730
  7. 7.√62 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 8.0 (d) 7.7
  8. 8.Best estimate of 2204 ÷ 36? (a) 550 (b) 5500 (c) 55
  9. 9.√69 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 8.3 (d) 8.2
  10. 10.Best estimate of 4589 ÷ 82? (a) 57 (b) 570 (c) 5700
  11. 11.√58 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.5 (d) 7.7
  12. 12.Best estimate of 523 ÷ 42? (a) 1300 (b) 130 (c) 13
  13. 13.Best estimate of 1934 ÷ 32? (a) 6400 (b) 640 (c) 64
  14. 14.Best estimate of 2978 ÷ 33? (a) 990 (b) 9900 (c) 99
  15. 15.Best estimate of 3531 ÷ 53? (a) 710 (b) 71 (c) 7100
  16. 16.√98 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.9 (d) 10.2
  17. 17.Best estimate of 3105 ÷ 56? (a) 520 (b) 5200 (c) 52
  18. 18.Best estimate of 2824 ÷ 63? (a) 47 (b) 470 (c) 4700
  19. 19.Best estimate of 4492 ÷ 52? (a) 900 (b) 9000 (c) 90
  20. 20.Best estimate of 2344 ÷ 41? (a) 590 (b) 59 (c) 5900
  21. 21.√53 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.3 (d) 7.6
  22. 22.Best estimate of 2072 ÷ 64? (a) 35 (b) 3500 (c) 350
  23. 23.√78 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 9.0 (d) 8.8
  24. 24.Best estimate of 6582 ÷ 69? (a) 940 (b) 94 (c) 9400
  25. 25.Best estimate of 3243 ÷ 62? (a) 540 (b) 54 (c) 5400
  26. 26.Best estimate of 4863 ÷ 52? (a) 97 (b) 970 (c) 9700
  27. 27.√55 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.6
  28. 28.√30 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.7
  29. 29.Best estimate of 6790 ÷ 82? (a) 8500 (b) 850 (c) 85
  30. 30.Best estimate of 3426 ÷ 38? (a) 8600 (b) 86 (c) 860
  31. 31.Best estimate of 2018 ÷ 42? (a) 50 (b) 500 (c) 5000
  32. 32.Best estimate of 3935 ÷ 81? (a) 49 (b) 490 (c) 4900
  33. 33.Best estimate of 5769 ÷ 76? (a) 720 (b) 7200 (c) 72
  34. 34.Best estimate of 2474 ÷ 26? (a) 82 (b) 8200 (c) 820
  35. 35.Best estimate of 1793 ÷ 39? (a) 450 (b) 45 (c) 4500
  36. 36.Best estimate of 1764 ÷ 23? (a) 88 (b) 8800 (c) 880
  37. 37.Best estimate of 2880 ÷ 77? (a) 360 (b) 36 (c) 3600
  38. 38.√59 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.9 (d) 8.0
  39. 39.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.0
  40. 40.Best estimate of 1371 ÷ 86? (a) 150 (b) 1500 (c) 15

Answer key

  1. 8.7
  2. 6.6
  3. 8.9
  4. 23
  5. 58
  6. 73
  7. 7.9
  8. 55
  9. 8.3
  10. 57
  11. 7.6
  12. 13
  13. 64
  14. 99
  15. 71
  16. 9.9
  17. 52
  18. 47
  19. 90
  20. 59
  21. 7.3
  22. 35
  23. 8.8
  24. 94
  25. 54
  26. 97
  27. 7.4
  28. 5.5
  29. 85
  30. 86
  31. 50
  32. 49
  33. 72
  34. 82
  35. 45
  36. 88
  37. 36
  38. 7.7
  39. 9.1
  40. 15

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