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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 428 · 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 1113 ÷ 23? (a) 5600 (b) 560 (c) 56
  2. 2.Best estimate of 925 ÷ 57? (a) 150 (b) 1500 (c) 15
  3. 3.√50 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 7.2 (d) 7.1
  4. 4.√62 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  5. 5.√58 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.4
  6. 6.√70 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.2 (d) 8.4
  7. 7.√26 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.3 (d) 5.0
  8. 8.√89 to 1 decimal place? (a) 9.7 (b) 9.4 (c) 9.6 (d) 9.5
  9. 9.√94 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.8 (d) 9.7
  10. 10.Best estimate of 3402 ÷ 52? (a) 6800 (b) 68 (c) 680
  11. 11.Best estimate of 1050 ÷ 34? (a) 3500 (b) 35 (c) 350
  12. 12.√32 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.7 (d) 5.9
  13. 13.Best estimate of 3497 ÷ 41? (a) 87 (b) 870 (c) 8700
  14. 14.√56 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.5 (d) 7.6
  15. 15.Best estimate of 542 ÷ 33? (a) 1800 (b) 18 (c) 180
  16. 16.Best estimate of 2623 ÷ 28? (a) 87 (b) 870 (c) 8700
  17. 17.Best estimate of 1337 ÷ 82? (a) 170 (b) 17 (c) 1700
  18. 18.Best estimate of 1819 ÷ 54? (a) 3600 (b) 36 (c) 360
  19. 19.√23 to 1 decimal place? (a) 5.1 (b) 4.8 (c) 5.0 (d) 4.9
  20. 20.Best estimate of 4436 ÷ 53? (a) 8900 (b) 890 (c) 89
  21. 21.√75 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  22. 22.√96 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 10.0 (d) 10.1
  23. 23.Best estimate of 4035 ÷ 68? (a) 5800 (b) 580 (c) 58
  24. 24.Best estimate of 5990 ÷ 81? (a) 750 (b) 75 (c) 7500
  25. 25.√77 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.8 (d) 9.0
  26. 26.Best estimate of 2913 ÷ 34? (a) 970 (b) 9700 (c) 97
  27. 27.Best estimate of 1332 ÷ 82? (a) 1700 (b) 170 (c) 17
  28. 28.Best estimate of 3439 ÷ 54? (a) 690 (b) 69 (c) 6900
  29. 29.Best estimate of 1987 ÷ 36? (a) 500 (b) 50 (c) 5000
  30. 30.√74 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.5 (d) 8.3
  31. 31.Best estimate of 1162 ÷ 36? (a) 29 (b) 290 (c) 2900
  32. 32.√40 to 1 decimal place? (a) 6.3 (b) 6.0 (c) 6.2 (d) 6.1
  33. 33.√28 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.3 (d) 5.2
  34. 34.√90 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.5 (d) 9.6
  35. 35.√85 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.2 (d) 9.0
  36. 36.√98 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.7 (d) 10.0
  37. 37.√69 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.4 (d) 8.3
  38. 38.√42 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.8 (d) 6.6
  39. 39.Best estimate of 1122 ÷ 79? (a) 1400 (b) 14 (c) 140
  40. 40.√48 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.1 (d) 7.0

Answer key

  1. 56
  2. 15
  3. 7.1
  4. 7.9
  5. 7.6
  6. 8.4
  7. 5.1
  8. 9.4
  9. 9.7
  10. 68
  11. 35
  12. 5.7
  13. 87
  14. 7.5
  15. 18
  16. 87
  17. 17
  18. 36
  19. 4.8
  20. 89
  21. 8.7
  22. 9.8
  23. 58
  24. 75
  25. 8.8
  26. 97
  27. 17
  28. 69
  29. 50
  30. 8.6
  31. 29
  32. 6.3
  33. 5.3
  34. 9.5
  35. 9.2
  36. 9.9
  37. 8.3
  38. 6.5
  39. 14
  40. 6.9

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