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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 468 · 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 2294 ÷ 37? (a) 5700 (b) 57 (c) 570
  2. 2.Best estimate of 4954 ÷ 78? (a) 62 (b) 6200 (c) 620
  3. 3.√38 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  4. 4.√63 to 1 decimal place? (a) 7.9 (b) 8.2 (c) 8.1 (d) 8.0
  5. 5.Best estimate of 2388 ÷ 31? (a) 8000 (b) 800 (c) 80
  6. 6.√21 to 1 decimal place? (a) 4.9 (b) 4.6 (c) 4.8 (d) 4.7
  7. 7.Best estimate of 3210 ÷ 84? (a) 4000 (b) 400 (c) 40
  8. 8.√84 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.0
  9. 9.Best estimate of 3716 ÷ 62? (a) 620 (b) 6200 (c) 62
  10. 10.√79 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.9 (d) 9.1
  11. 11.Best estimate of 1524 ÷ 62? (a) 25 (b) 2500 (c) 250
  12. 12.Best estimate of 5957 ÷ 82? (a) 7400 (b) 74 (c) 740
  13. 13.√22 to 1 decimal place? (a) 4.8 (b) 4.7 (c) 5.0 (d) 4.9
  14. 14.√40 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.6 (d) 6.4
  15. 15.Best estimate of 2396 ÷ 26? (a) 80 (b) 8000 (c) 800
  16. 16.Best estimate of 1317 ÷ 61? (a) 2200 (b) 220 (c) 22
  17. 17.√35 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.9 (d) 6.1
  18. 18.Best estimate of 4427 ÷ 73? (a) 630 (b) 6300 (c) 63
  19. 19.Best estimate of 945 ÷ 72? (a) 140 (b) 14 (c) 1400
  20. 20.Best estimate of 1127 ÷ 76? (a) 1400 (b) 14 (c) 140
  21. 21.Best estimate of 4856 ÷ 86? (a) 54 (b) 540 (c) 5400
  22. 22.√28 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.3 (d) 5.5
  23. 23.√27 to 1 decimal place? (a) 5.1 (b) 5.3 (c) 5.4 (d) 5.2
  24. 24.√45 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.4 (d) 6.7
  25. 25.Best estimate of 2850 ÷ 31? (a) 950 (b) 9500 (c) 95
  26. 26.Best estimate of 2773 ÷ 33? (a) 9200 (b) 92 (c) 920
  27. 27.Best estimate of 1588 ÷ 27? (a) 530 (b) 5300 (c) 53
  28. 28.√88 to 1 decimal place? (a) 9.5 (b) 9.2 (c) 9.3 (d) 9.4
  29. 29.Best estimate of 4479 ÷ 52? (a) 900 (b) 9000 (c) 90
  30. 30.Best estimate of 1563 ÷ 54? (a) 3100 (b) 31 (c) 310
  31. 31.Best estimate of 2932 ÷ 32? (a) 980 (b) 9800 (c) 98
  32. 32.√44 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 6.6 (d) 6.7
  33. 33.Best estimate of 4761 ÷ 56? (a) 79 (b) 790 (c) 7900
  34. 34.Best estimate of 2083 ÷ 34? (a) 690 (b) 6900 (c) 69
  35. 35.√29 to 1 decimal place? (a) 5.3 (b) 5.6 (c) 5.5 (d) 5.4
  36. 36.√55 to 1 decimal place? (a) 7.3 (b) 7.4 (c) 7.5 (d) 7.6
  37. 37.Best estimate of 1358 ÷ 47? (a) 270 (b) 2700 (c) 27
  38. 38.√87 to 1 decimal place? (a) 9.3 (b) 9.5 (c) 9.4 (d) 9.2
  39. 39.√52 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.2
  40. 40.√92 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.7 (d) 9.4

Answer key

  1. 57
  2. 62
  3. 6.2
  4. 7.9
  5. 80
  6. 4.6
  7. 40
  8. 9.2
  9. 62
  10. 8.9
  11. 25
  12. 74
  13. 4.7
  14. 6.3
  15. 80
  16. 22
  17. 5.9
  18. 63
  19. 14
  20. 14
  21. 54
  22. 5.3
  23. 5.2
  24. 6.7
  25. 95
  26. 92
  27. 53
  28. 9.4
  29. 90
  30. 31
  31. 98
  32. 6.6
  33. 79
  34. 69
  35. 5.4
  36. 7.4
  37. 27
  38. 9.3
  39. 7.2
  40. 9.6

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