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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 68 · 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 1481 ÷ 47? (a) 3000 (b) 30 (c) 300
  2. 2.Best estimate of 1074 ÷ 33? (a) 360 (b) 3600 (c) 36
  3. 3.Best estimate of 1156 ÷ 21? (a) 580 (b) 5800 (c) 58
  4. 4.Best estimate of 605 ÷ 33? (a) 200 (b) 20 (c) 2000
  5. 5.Best estimate of 2241 ÷ 52? (a) 450 (b) 4500 (c) 45
  6. 6.Best estimate of 1811 ÷ 64? (a) 3000 (b) 30 (c) 300
  7. 7.Best estimate of 5264 ÷ 64? (a) 880 (b) 8800 (c) 88
  8. 8.Best estimate of 4213 ÷ 74? (a) 600 (b) 6000 (c) 60
  9. 9.Best estimate of 6013 ÷ 81? (a) 7500 (b) 75 (c) 750
  10. 10.Best estimate of 5943 ÷ 66? (a) 850 (b) 8500 (c) 85
  11. 11.√22 to 1 decimal place? (a) 4.6 (b) 4.5 (c) 4.4 (d) 4.7
  12. 12.Best estimate of 2646 ÷ 32? (a) 88 (b) 8800 (c) 880
  13. 13.Best estimate of 1396 ÷ 86? (a) 160 (b) 16 (c) 1600
  14. 14.√40 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.4 (d) 6.2
  15. 15.Best estimate of 6756 ÷ 83? (a) 84 (b) 840 (c) 8400
  16. 16.√26 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 4.8 (d) 5.1
  17. 17.√61 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.5 (d) 7.6
  18. 18.Best estimate of 656 ÷ 22? (a) 330 (b) 33 (c) 3300
  19. 19.Best estimate of 2195 ÷ 51? (a) 440 (b) 44 (c) 4400
  20. 20.√31 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.8 (d) 5.7
  21. 21.Best estimate of 2065 ÷ 27? (a) 69 (b) 690 (c) 6900
  22. 22.√32 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.9 (d) 5.8
  23. 23.Best estimate of 4509 ÷ 49? (a) 90 (b) 900 (c) 9000
  24. 24.√84 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.1
  25. 25.Best estimate of 2246 ÷ 86? (a) 25 (b) 2500 (c) 250
  26. 26.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 10.0
  27. 27.√20 to 1 decimal place? (a) 4.4 (b) 4.5 (c) 4.3 (d) 4.2
  28. 28.Best estimate of 2023 ÷ 69? (a) 29 (b) 2900 (c) 290
  29. 29.Best estimate of 664 ÷ 44? (a) 17 (b) 1700 (c) 170
  30. 30.√27 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.5 (d) 5.3
  31. 31.√52 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 7.0 (d) 7.2
  32. 32.Best estimate of 6426 ÷ 88? (a) 710 (b) 7100 (c) 71
  33. 33.√48 to 1 decimal place? (a) 6.9 (b) 6.7 (c) 6.8 (d) 7.0
  34. 34.Best estimate of 4722 ÷ 56? (a) 790 (b) 79 (c) 7900
  35. 35.√24 to 1 decimal place? (a) 4.9 (b) 5.2 (c) 5.1 (d) 5.0
  36. 36.Best estimate of 3243 ÷ 52? (a) 6500 (b) 65 (c) 650
  37. 37.√92 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.8 (d) 9.6
  38. 38.Best estimate of 3784 ÷ 56? (a) 6300 (b) 630 (c) 63
  39. 39.√37 to 1 decimal place? (a) 6.4 (b) 6.2 (c) 6.3 (d) 6.1
  40. 40.Best estimate of 1230 ÷ 57? (a) 210 (b) 21 (c) 2100

Answer key

  1. 30
  2. 36
  3. 58
  4. 20
  5. 45
  6. 30
  7. 88
  8. 60
  9. 75
  10. 85
  11. 4.7
  12. 88
  13. 16
  14. 6.3
  15. 84
  16. 5.1
  17. 7.8
  18. 33
  19. 44
  20. 5.6
  21. 69
  22. 5.7
  23. 90
  24. 9.2
  25. 25
  26. 9.9
  27. 4.5
  28. 29
  29. 17
  30. 5.2
  31. 7.2
  32. 71
  33. 6.9
  34. 79
  35. 4.9
  36. 65
  37. 9.6
  38. 63
  39. 6.1
  40. 21

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