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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 762 · 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 4606 ÷ 49? (a) 92 (b) 920 (c) 9200
  2. 2.Best estimate of 561 ÷ 26? (a) 1900 (b) 190 (c) 19
  3. 3.Best estimate of 749 ÷ 33? (a) 250 (b) 25 (c) 2500
  4. 4.√42 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.4 (d) 6.2
  5. 5.Best estimate of 958 ÷ 36? (a) 240 (b) 2400 (c) 24
  6. 6.Best estimate of 2054 ÷ 32? (a) 6800 (b) 68 (c) 680
  7. 7.Best estimate of 7014 ÷ 79? (a) 880 (b) 8800 (c) 88
  8. 8.Best estimate of 2667 ÷ 32? (a) 89 (b) 890 (c) 8900
  9. 9.√71 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.6 (d) 8.5
  10. 10.Best estimate of 2451 ÷ 73? (a) 35 (b) 3500 (c) 350
  11. 11.Best estimate of 1697 ÷ 59? (a) 2800 (b) 280 (c) 28
  12. 12.Best estimate of 2032 ÷ 27? (a) 6800 (b) 680 (c) 68
  13. 13.Best estimate of 464 ÷ 24? (a) 230 (b) 2300 (c) 23
  14. 14.Best estimate of 6151 ÷ 71? (a) 88 (b) 8800 (c) 880
  15. 15.√27 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.1 (d) 5.2
  16. 16.√89 to 1 decimal place? (a) 9.7 (b) 9.4 (c) 9.6 (d) 9.5
  17. 17.Best estimate of 3451 ÷ 39? (a) 8600 (b) 86 (c) 860
  18. 18.Best estimate of 2095 ÷ 22? (a) 105 (b) 1050 (c) 10500
  19. 19.Best estimate of 5391 ÷ 66? (a) 7700 (b) 770 (c) 77
  20. 20.Best estimate of 3278 ÷ 39? (a) 820 (b) 8200 (c) 82
  21. 21.Best estimate of 327 ÷ 23? (a) 160 (b) 16 (c) 1600
  22. 22.Best estimate of 1383 ÷ 21? (a) 69 (b) 690 (c) 6900
  23. 23.√75 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 8.7
  24. 24.Best estimate of 1043 ÷ 27? (a) 3500 (b) 350 (c) 35
  25. 25.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.0 (d) 6.3
  26. 26.Best estimate of 4256 ÷ 67? (a) 61 (b) 6100 (c) 610
  27. 27.√58 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.7 (d) 7.5
  28. 28.Best estimate of 3789 ÷ 57? (a) 630 (b) 6300 (c) 63
  29. 29.√65 to 1 decimal place? (a) 8.1 (b) 7.9 (c) 8.2 (d) 8.0
  30. 30.√94 to 1 decimal place? (a) 9.8 (b) 10.0 (c) 9.7 (d) 9.9
  31. 31.√82 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.2 (d) 9.4
  32. 32.Best estimate of 5179 ÷ 56? (a) 8600 (b) 860 (c) 86
  33. 33.Best estimate of 4762 ÷ 52? (a) 95 (b) 9500 (c) 950
  34. 34.Best estimate of 3515 ÷ 48? (a) 700 (b) 70 (c) 7000
  35. 35.√86 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.3 (d) 9.2
  36. 36.Best estimate of 2217 ÷ 32? (a) 7400 (b) 740 (c) 74
  37. 37.Best estimate of 1056 ÷ 42? (a) 260 (b) 2600 (c) 26
  38. 38.√41 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.5 (d) 6.4
  39. 39.Best estimate of 725 ÷ 47? (a) 15 (b) 150 (c) 1500
  40. 40.Best estimate of 1347 ÷ 76? (a) 17 (b) 1700 (c) 170

Answer key

  1. 92
  2. 19
  3. 25
  4. 6.5
  5. 24
  6. 68
  7. 88
  8. 89
  9. 8.4
  10. 35
  11. 28
  12. 68
  13. 23
  14. 88
  15. 5.2
  16. 9.4
  17. 86
  18. 105
  19. 77
  20. 82
  21. 16
  22. 69
  23. 8.7
  24. 35
  25. 6.1
  26. 61
  27. 7.6
  28. 63
  29. 8.1
  30. 9.7
  31. 9.1
  32. 86
  33. 95
  34. 70
  35. 9.3
  36. 74
  37. 26
  38. 6.4
  39. 15
  40. 17

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