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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 355 · 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.√96 to 1 decimal place? (a) 9.9 (b) 10.1 (c) 10.0 (d) 9.8
  2. 2.√42 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.5 (d) 6.3
  3. 3.Best estimate of 5682 ÷ 84? (a) 71 (b) 7100 (c) 710
  4. 4.Best estimate of 2308 ÷ 61? (a) 38 (b) 380 (c) 3800
  5. 5.√74 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.6
  6. 6.√40 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.4 (d) 6.5
  7. 7.Best estimate of 1747 ÷ 57? (a) 290 (b) 2900 (c) 29
  8. 8.Best estimate of 2595 ÷ 38? (a) 650 (b) 6500 (c) 65
  9. 9.Best estimate of 4148 ÷ 73? (a) 5900 (b) 59 (c) 590
  10. 10.√21 to 1 decimal place? (a) 4.3 (b) 4.6 (c) 4.5 (d) 4.4
  11. 11.Best estimate of 3458 ÷ 37? (a) 860 (b) 8600 (c) 86
  12. 12.Best estimate of 2644 ÷ 31? (a) 88 (b) 8800 (c) 880
  13. 13.√53 to 1 decimal place? (a) 7.1 (b) 7.4 (c) 7.3 (d) 7.2
  14. 14.Best estimate of 3396 ÷ 72? (a) 490 (b) 4900 (c) 49
  15. 15.Best estimate of 4505 ÷ 86? (a) 5000 (b) 50 (c) 500
  16. 16.Best estimate of 1896 ÷ 39? (a) 470 (b) 4700 (c) 47
  17. 17.√79 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.8 (d) 8.6
  18. 18.Best estimate of 1136 ÷ 27? (a) 38 (b) 3800 (c) 380
  19. 19.√59 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.4 (d) 7.5
  20. 20.Best estimate of 2190 ÷ 58? (a) 3700 (b) 37 (c) 370
  21. 21.√85 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 9.2 (d) 9.1
  22. 22.√98 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 10.1
  23. 23.√30 to 1 decimal place? (a) 5.4 (b) 5.6 (c) 5.5 (d) 5.3
  24. 24.Best estimate of 1763 ÷ 29? (a) 590 (b) 5900 (c) 59
  25. 25.Best estimate of 4309 ÷ 76? (a) 540 (b) 54 (c) 5400
  26. 26.Best estimate of 1596 ÷ 56? (a) 270 (b) 2700 (c) 27
  27. 27.Best estimate of 5935 ÷ 67? (a) 85 (b) 850 (c) 8500
  28. 28.√80 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.7 (d) 8.9
  29. 29.Best estimate of 820 ÷ 47? (a) 16 (b) 1600 (c) 160
  30. 30.√58 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.9 (d) 7.7
  31. 31.√24 to 1 decimal place? (a) 5.2 (b) 4.9 (c) 5.1 (d) 5.0
  32. 32.√35 to 1 decimal place? (a) 5.9 (b) 6.2 (c) 6.1 (d) 6.0
  33. 33.Best estimate of 446 ÷ 36? (a) 110 (b) 1100 (c) 11
  34. 34.√31 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.3
  35. 35.√41 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.4 (d) 6.5
  36. 36.Best estimate of 2908 ÷ 31? (a) 9700 (b) 97 (c) 970
  37. 37.√27 to 1 decimal place? (a) 5.4 (b) 5.2 (c) 5.5 (d) 5.3
  38. 38.Best estimate of 1110 ÷ 84? (a) 1400 (b) 140 (c) 14
  39. 39.Best estimate of 1052 ÷ 36? (a) 26 (b) 2600 (c) 260
  40. 40.√55 to 1 decimal place? (a) 7.7 (b) 7.4 (c) 7.5 (d) 7.6

Answer key

  1. 9.8
  2. 6.5
  3. 71
  4. 38
  5. 8.6
  6. 6.3
  7. 29
  8. 65
  9. 59
  10. 4.6
  11. 86
  12. 88
  13. 7.3
  14. 49
  15. 50
  16. 47
  17. 8.9
  18. 38
  19. 7.7
  20. 37
  21. 9.2
  22. 9.9
  23. 5.5
  24. 59
  25. 54
  26. 27
  27. 85
  28. 8.9
  29. 16
  30. 7.6
  31. 4.9
  32. 5.9
  33. 11
  34. 5.6
  35. 6.4
  36. 97
  37. 5.2
  38. 14
  39. 26
  40. 7.4

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