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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 23 · 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.√94 to 1 decimal place? (a) 9.9 (b) 9.6 (c) 9.7 (d) 9.8
  2. 2.√20 to 1 decimal place? (a) 4.3 (b) 4.6 (c) 4.5 (d) 4.4
  3. 3.√92 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.5 (d) 9.4
  4. 4.Best estimate of 5997 ÷ 77? (a) 750 (b) 75 (c) 7500
  5. 5.Best estimate of 4629 ÷ 52? (a) 93 (b) 9300 (c) 930
  6. 6.√63 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 8.0 (d) 7.8
  7. 7.√58 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.8 (d) 7.6
  8. 8.√65 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.9 (d) 8.2
  9. 9.√72 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.4 (d) 8.2
  10. 10.Best estimate of 466 ÷ 26? (a) 160 (b) 16 (c) 1600
  11. 11.√51 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 7.0 (d) 7.1
  12. 12.√31 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.7 (d) 5.8
  13. 13.Best estimate of 803 ÷ 66? (a) 110 (b) 1100 (c) 11
  14. 14.Best estimate of 2419 ÷ 38? (a) 6000 (b) 600 (c) 60
  15. 15.Best estimate of 6775 ÷ 88? (a) 7500 (b) 75 (c) 750
  16. 16.√79 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.9 (d) 8.7
  17. 17.√50 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.0 (d) 7.3
  18. 18.√59 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.4
  19. 19.Best estimate of 1507 ÷ 41? (a) 38 (b) 3800 (c) 380
  20. 20.Best estimate of 1502 ÷ 26? (a) 50 (b) 5000 (c) 500
  21. 21.Best estimate of 2104 ÷ 26? (a) 700 (b) 70 (c) 7000
  22. 22.Best estimate of 1158 ÷ 66? (a) 170 (b) 1700 (c) 17
  23. 23.√40 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.1 (d) 6.3
  24. 24.√69 to 1 decimal place? (a) 8.3 (b) 8.6 (c) 8.4 (d) 8.5
  25. 25.Best estimate of 3547 ÷ 37? (a) 8900 (b) 89 (c) 890
  26. 26.√78 to 1 decimal place? (a) 8.9 (b) 8.7 (c) 8.6 (d) 8.8
  27. 27.Best estimate of 1653 ÷ 36? (a) 410 (b) 4100 (c) 41
  28. 28.Best estimate of 3806 ÷ 72? (a) 540 (b) 54 (c) 5400
  29. 29.√41 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.2 (d) 6.5
  30. 30.Best estimate of 1444 ÷ 39? (a) 360 (b) 3600 (c) 36
  31. 31.Best estimate of 3414 ÷ 46? (a) 6800 (b) 68 (c) 680
  32. 32.√62 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.6 (d) 7.8
  33. 33.√45 to 1 decimal place? (a) 6.8 (b) 6.7 (c) 6.9 (d) 7.0
  34. 34.Best estimate of 4016 ÷ 52? (a) 80 (b) 8000 (c) 800
  35. 35.√56 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.6
  36. 36.Best estimate of 1278 ÷ 38? (a) 3200 (b) 320 (c) 32
  37. 37.Best estimate of 2721 ÷ 66? (a) 3900 (b) 39 (c) 390
  38. 38.√29 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.5 (d) 5.2
  39. 39.Best estimate of 5278 ÷ 66? (a) 7500 (b) 750 (c) 75
  40. 40.Best estimate of 1004 ÷ 24? (a) 500 (b) 50 (c) 5000

Answer key

  1. 9.7
  2. 4.5
  3. 9.6
  4. 75
  5. 93
  6. 7.9
  7. 7.6
  8. 8.1
  9. 8.5
  10. 16
  11. 7.1
  12. 5.6
  13. 11
  14. 60
  15. 75
  16. 8.9
  17. 7.1
  18. 7.7
  19. 38
  20. 50
  21. 70
  22. 17
  23. 6.3
  24. 8.3
  25. 89
  26. 8.8
  27. 41
  28. 54
  29. 6.4
  30. 36
  31. 68
  32. 7.9
  33. 6.7
  34. 80
  35. 7.5
  36. 32
  37. 39
  38. 5.4
  39. 75
  40. 50

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