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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 634 · 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 1290 ÷ 37? (a) 320 (b) 3200 (c) 32
  2. 2.√92 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.4 (d) 9.7
  3. 3.Best estimate of 2958 ÷ 71? (a) 4200 (b) 420 (c) 42
  4. 4.Best estimate of 6348 ÷ 69? (a) 91 (b) 9100 (c) 910
  5. 5.√55 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.6 (d) 7.4
  6. 6.√29 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.4
  7. 7.Best estimate of 4673 ÷ 54? (a) 930 (b) 9300 (c) 93
  8. 8.Best estimate of 3400 ÷ 67? (a) 490 (b) 49 (c) 4900
  9. 9.Best estimate of 1220 ÷ 21? (a) 6100 (b) 610 (c) 61
  10. 10.Best estimate of 3438 ÷ 73? (a) 49 (b) 490 (c) 4900
  11. 11.√44 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.9 (d) 6.6
  12. 12.Best estimate of 3363 ÷ 56? (a) 560 (b) 56 (c) 5600
  13. 13.Best estimate of 2291 ÷ 37? (a) 570 (b) 5700 (c) 57
  14. 14.√70 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.6 (d) 8.4
  15. 15.Best estimate of 7626 ÷ 82? (a) 9500 (b) 95 (c) 950
  16. 16.Best estimate of 6772 ÷ 82? (a) 8500 (b) 850 (c) 85
  17. 17.Best estimate of 5930 ÷ 88? (a) 660 (b) 66 (c) 6600
  18. 18.√41 to 1 decimal place? (a) 6.4 (b) 6.1 (c) 6.2 (d) 6.3
  19. 19.Best estimate of 1332 ÷ 36? (a) 330 (b) 3300 (c) 33
  20. 20.√96 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.8 (d) 9.9
  21. 21.Best estimate of 1727 ÷ 27? (a) 580 (b) 58 (c) 5800
  22. 22.√85 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.2
  23. 23.√40 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.3 (d) 6.2
  24. 24.Best estimate of 1931 ÷ 27? (a) 64 (b) 640 (c) 6400
  25. 25.Best estimate of 3588 ÷ 52? (a) 7200 (b) 72 (c) 720
  26. 26.√82 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.8 (d) 9.1
  27. 27.Best estimate of 1276 ÷ 71? (a) 18 (b) 180 (c) 1800
  28. 28.Best estimate of 1843 ÷ 24? (a) 92 (b) 9200 (c) 920
  29. 29.Best estimate of 1754 ÷ 48? (a) 350 (b) 3500 (c) 35
  30. 30.Best estimate of 1278 ÷ 52? (a) 2600 (b) 26 (c) 260
  31. 31.√61 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  32. 32.√43 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.5 (d) 6.7
  33. 33.Best estimate of 2157 ÷ 26? (a) 72 (b) 720 (c) 7200
  34. 34.√31 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.4 (d) 5.6
  35. 35.Best estimate of 6304 ÷ 83? (a) 7900 (b) 790 (c) 79
  36. 36.√72 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.2
  37. 37.Best estimate of 1611 ÷ 31? (a) 5400 (b) 540 (c) 54
  38. 38.Best estimate of 932 ÷ 36? (a) 2300 (b) 23 (c) 230
  39. 39.Best estimate of 511 ÷ 32? (a) 17 (b) 1700 (c) 170
  40. 40.√89 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.5

Answer key

  1. 32
  2. 9.6
  3. 42
  4. 91
  5. 7.4
  6. 5.4
  7. 93
  8. 49
  9. 61
  10. 49
  11. 6.6
  12. 56
  13. 57
  14. 8.4
  15. 95
  16. 85
  17. 66
  18. 6.4
  19. 33
  20. 9.8
  21. 58
  22. 9.2
  23. 6.3
  24. 64
  25. 72
  26. 9.1
  27. 18
  28. 92
  29. 35
  30. 26
  31. 7.8
  32. 6.6
  33. 72
  34. 5.6
  35. 79
  36. 8.5
  37. 54
  38. 23
  39. 17
  40. 9.4

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