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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 967 · 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.√74 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.3
  2. 2.Best estimate of 3529 ÷ 62? (a) 5900 (b) 590 (c) 59
  3. 3.√72 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.6 (d) 8.5
  4. 4.√35 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.9 (d) 6.1
  5. 5.√23 to 1 decimal place? (a) 4.7 (b) 4.5 (c) 4.8 (d) 4.6
  6. 6.Best estimate of 3592 ÷ 78? (a) 45 (b) 4500 (c) 450
  7. 7.√92 to 1 decimal place? (a) 9.5 (b) 9.8 (c) 9.6 (d) 9.7
  8. 8.√44 to 1 decimal place? (a) 6.3 (b) 6.6 (c) 6.4 (d) 6.5
  9. 9.√80 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.9 (d) 8.8
  10. 10.√59 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.5 (d) 7.7
  11. 11.Best estimate of 5631 ÷ 88? (a) 6300 (b) 630 (c) 63
  12. 12.√55 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.5 (d) 7.7
  13. 13.√82 to 1 decimal place? (a) 9.1 (b) 9.0 (c) 8.8 (d) 8.9
  14. 14.Best estimate of 6130 ÷ 73? (a) 880 (b) 88 (c) 8800
  15. 15.√84 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.2 (d) 9.1
  16. 16.Best estimate of 862 ÷ 48? (a) 1700 (b) 170 (c) 17
  17. 17.Best estimate of 2900 ÷ 46? (a) 58 (b) 580 (c) 5800
  18. 18.Best estimate of 1401 ÷ 38? (a) 3500 (b) 350 (c) 35
  19. 19.√30 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.6 (d) 5.4
  20. 20.Best estimate of 5345 ÷ 66? (a) 76 (b) 7600 (c) 760
  21. 21.√63 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 8.2
  22. 22.Best estimate of 3041 ÷ 74? (a) 4300 (b) 43 (c) 430
  23. 23.Best estimate of 3948 ÷ 44? (a) 990 (b) 9900 (c) 99
  24. 24.√98 to 1 decimal place? (a) 10.0 (b) 9.7 (c) 9.8 (d) 9.9
  25. 25.Best estimate of 761 ÷ 33? (a) 2500 (b) 25 (c) 250
  26. 26.√31 to 1 decimal place? (a) 5.8 (b) 5.6 (c) 5.9 (d) 5.7
  27. 27.√41 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.6 (d) 6.5
  28. 28.Best estimate of 650 ÷ 36? (a) 16 (b) 160 (c) 1600
  29. 29.√94 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 10.0 (d) 9.7
  30. 30.Best estimate of 1327 ÷ 41? (a) 33 (b) 3300 (c) 330
  31. 31.Best estimate of 2307 ÷ 64? (a) 3800 (b) 38 (c) 380
  32. 32.Best estimate of 1758 ÷ 47? (a) 3500 (b) 35 (c) 350
  33. 33.√78 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 8.6 (d) 8.7
  34. 34.Best estimate of 836 ÷ 46? (a) 170 (b) 1700 (c) 17
  35. 35.Best estimate of 3500 ÷ 76? (a) 4400 (b) 44 (c) 440
  36. 36.√79 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  37. 37.Best estimate of 1392 ÷ 21? (a) 700 (b) 7000 (c) 70
  38. 38.Best estimate of 2632 ÷ 53? (a) 5300 (b) 53 (c) 530
  39. 39.Best estimate of 1563 ÷ 38? (a) 3900 (b) 39 (c) 390
  40. 40.Best estimate of 2004 ÷ 57? (a) 330 (b) 3300 (c) 33

Answer key

  1. 8.6
  2. 59
  3. 8.5
  4. 5.9
  5. 4.8
  6. 45
  7. 9.6
  8. 6.6
  9. 8.9
  10. 7.7
  11. 63
  12. 7.4
  13. 9.1
  14. 88
  15. 9.2
  16. 17
  17. 58
  18. 35
  19. 5.5
  20. 76
  21. 7.9
  22. 43
  23. 99
  24. 9.9
  25. 25
  26. 5.6
  27. 6.4
  28. 16
  29. 9.7
  30. 33
  31. 38
  32. 35
  33. 8.8
  34. 17
  35. 44
  36. 8.9
  37. 70
  38. 53
  39. 39
  40. 33

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