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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 293 · 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) 4.4 (c) 4.6 (d) 4.5
  2. 2.√44 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.3 (d) 6.5
  3. 3.√55 to 1 decimal place? (a) 7.7 (b) 7.5 (c) 7.6 (d) 7.4
  4. 4.√53 to 1 decimal place? (a) 7.3 (b) 7.6 (c) 7.4 (d) 7.5
  5. 5.Best estimate of 1233 ÷ 73? (a) 180 (b) 1800 (c) 18
  6. 6.Best estimate of 3991 ÷ 74? (a) 5700 (b) 57 (c) 570
  7. 7.Best estimate of 2291 ÷ 63? (a) 38 (b) 3800 (c) 380
  8. 8.√88 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.4 (d) 9.5
  9. 9.Best estimate of 4193 ÷ 72? (a) 600 (b) 6000 (c) 60
  10. 10.Best estimate of 1184 ÷ 31? (a) 390 (b) 3900 (c) 39
  11. 11.√32 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.8
  12. 12.√89 to 1 decimal place? (a) 9.6 (b) 9.4 (c) 9.3 (d) 9.5
  13. 13.√98 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 10.2 (d) 10.1
  14. 14.√48 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.7 (d) 6.8
  15. 15.Best estimate of 1164 ÷ 41? (a) 29 (b) 290 (c) 2900
  16. 16.√50 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 7.1 (d) 7.2
  17. 17.Best estimate of 2200 ÷ 46? (a) 44 (b) 4400 (c) 440
  18. 18.Best estimate of 1733 ÷ 36? (a) 43 (b) 4300 (c) 430
  19. 19.Best estimate of 5698 ÷ 66? (a) 8100 (b) 810 (c) 81
  20. 20.Best estimate of 1385 ÷ 73? (a) 2000 (b) 200 (c) 20
  21. 21.Best estimate of 4974 ÷ 57? (a) 8300 (b) 83 (c) 830
  22. 22.Best estimate of 1519 ÷ 44? (a) 380 (b) 3800 (c) 38
  23. 23.Best estimate of 2875 ÷ 56? (a) 4800 (b) 48 (c) 480
  24. 24.Best estimate of 738 ÷ 23? (a) 37 (b) 3700 (c) 370
  25. 25.√58 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.5 (d) 7.4
  26. 26.Best estimate of 2099 ÷ 32? (a) 70 (b) 700 (c) 7000
  27. 27.Best estimate of 1198 ÷ 42? (a) 300 (b) 3000 (c) 30
  28. 28.√65 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  29. 29.Best estimate of 787 ÷ 38? (a) 200 (b) 20 (c) 2000
  30. 30.Best estimate of 2504 ÷ 43? (a) 63 (b) 6300 (c) 630
  31. 31.√27 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.3 (d) 5.4
  32. 32.Best estimate of 572 ÷ 37? (a) 1400 (b) 140 (c) 14
  33. 33.√37 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 5.9 (d) 6.0
  34. 34.Best estimate of 3692 ÷ 39? (a) 92 (b) 920 (c) 9200
  35. 35.Best estimate of 763 ÷ 29? (a) 2500 (b) 250 (c) 25
  36. 36.Best estimate of 3309 ÷ 56? (a) 55 (b) 5500 (c) 550
  37. 37.Best estimate of 2502 ÷ 43? (a) 6300 (b) 63 (c) 630
  38. 38.√75 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  39. 39.√51 to 1 decimal place? (a) 7.0 (b) 7.3 (c) 7.1 (d) 7.2
  40. 40.Best estimate of 1927 ÷ 32? (a) 6400 (b) 64 (c) 640

Answer key

  1. 4.7
  2. 6.6
  3. 7.4
  4. 7.3
  5. 18
  6. 57
  7. 38
  8. 9.4
  9. 60
  10. 39
  11. 5.7
  12. 9.4
  13. 9.9
  14. 6.9
  15. 29
  16. 7.1
  17. 44
  18. 43
  19. 81
  20. 20
  21. 83
  22. 38
  23. 48
  24. 37
  25. 7.6
  26. 70
  27. 30
  28. 8.1
  29. 20
  30. 63
  31. 5.2
  32. 14
  33. 6.1
  34. 92
  35. 25
  36. 55
  37. 63
  38. 8.7
  39. 7.1
  40. 64

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