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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 969 · 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.√22 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.5 (d) 4.6
  2. 2.√28 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.0 (d) 5.2
  3. 3.Best estimate of 1299 ÷ 51? (a) 260 (b) 26 (c) 2600
  4. 4.√84 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.4 (d) 9.5
  5. 5.√63 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 8.0
  6. 6.Best estimate of 2142 ÷ 51? (a) 43 (b) 4300 (c) 430
  7. 7.√51 to 1 decimal place? (a) 7.3 (b) 7.0 (c) 7.1 (d) 7.2
  8. 8.√65 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 8.1 (d) 8.0
  9. 9.√20 to 1 decimal place? (a) 4.5 (b) 4.7 (c) 4.4 (d) 4.6
  10. 10.Best estimate of 1975 ÷ 86? (a) 220 (b) 2200 (c) 22
  11. 11.√98 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 10.0
  12. 12.√56 to 1 decimal place? (a) 7.3 (b) 7.5 (c) 7.4 (d) 7.6
  13. 13.Best estimate of 3070 ÷ 37? (a) 7700 (b) 77 (c) 770
  14. 14.Best estimate of 2114 ÷ 57? (a) 3500 (b) 350 (c) 35
  15. 15.Best estimate of 1758 ÷ 24? (a) 88 (b) 8800 (c) 880
  16. 16.Best estimate of 3721 ÷ 48? (a) 7400 (b) 740 (c) 74
  17. 17.√30 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.7 (d) 5.6
  18. 18.√52 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.1 (d) 7.2
  19. 19.√45 to 1 decimal place? (a) 6.4 (b) 6.7 (c) 6.6 (d) 6.5
  20. 20.Best estimate of 1131 ÷ 21? (a) 570 (b) 5700 (c) 57
  21. 21.Best estimate of 2349 ÷ 87? (a) 2600 (b) 26 (c) 260
  22. 22.Best estimate of 2936 ÷ 33? (a) 9800 (b) 98 (c) 980
  23. 23.Best estimate of 818 ÷ 31? (a) 2700 (b) 270 (c) 27
  24. 24.√50 to 1 decimal place? (a) 7.3 (b) 7.1 (c) 7.4 (d) 7.2
  25. 25.Best estimate of 5536 ÷ 81? (a) 690 (b) 6900 (c) 69
  26. 26.Best estimate of 838 ÷ 27? (a) 280 (b) 2800 (c) 28
  27. 27.Best estimate of 905 ÷ 36? (a) 23 (b) 230 (c) 2300
  28. 28.√87 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.0
  29. 29.√24 to 1 decimal place? (a) 4.8 (b) 5.0 (c) 5.1 (d) 4.9
  30. 30.Best estimate of 5592 ÷ 87? (a) 6200 (b) 620 (c) 62
  31. 31.Best estimate of 1782 ÷ 62? (a) 300 (b) 3000 (c) 30
  32. 32.Best estimate of 1290 ÷ 67? (a) 1800 (b) 180 (c) 18
  33. 33.Best estimate of 2337 ÷ 77? (a) 29 (b) 290 (c) 2900
  34. 34.√86 to 1 decimal place? (a) 9.2 (b) 9.5 (c) 9.3 (d) 9.4
  35. 35.√34 to 1 decimal place? (a) 5.8 (b) 5.5 (c) 5.7 (d) 5.6
  36. 36.√35 to 1 decimal place? (a) 5.7 (b) 6.0 (c) 5.9 (d) 5.8
  37. 37.√48 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.9 (d) 6.6
  38. 38.Best estimate of 1694 ÷ 46? (a) 3400 (b) 340 (c) 34
  39. 39.√69 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.1 (d) 8.2
  40. 40.√47 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 6.9 (d) 7.0

Answer key

  1. 4.7
  2. 5.3
  3. 26
  4. 9.2
  5. 7.9
  6. 43
  7. 7.1
  8. 8.1
  9. 4.5
  10. 22
  11. 9.9
  12. 7.5
  13. 77
  14. 35
  15. 88
  16. 74
  17. 5.5
  18. 7.2
  19. 6.7
  20. 57
  21. 26
  22. 98
  23. 27
  24. 7.1
  25. 69
  26. 28
  27. 23
  28. 9.3
  29. 4.9
  30. 62
  31. 30
  32. 18
  33. 29
  34. 9.3
  35. 5.8
  36. 5.9
  37. 6.9
  38. 34
  39. 8.3
  40. 6.9

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