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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 523 · 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 1690 ÷ 61? (a) 2800 (b) 28 (c) 280
  2. 2.Best estimate of 1970 ÷ 26? (a) 660 (b) 6600 (c) 66
  3. 3.Best estimate of 1905 ÷ 77? (a) 2400 (b) 24 (c) 240
  4. 4.Best estimate of 1781 ÷ 77? (a) 220 (b) 2200 (c) 22
  5. 5.√23 to 1 decimal place? (a) 4.8 (b) 5.0 (c) 4.9 (d) 5.1
  6. 6.Best estimate of 2933 ÷ 43? (a) 73 (b) 730 (c) 7300
  7. 7.Best estimate of 1492 ÷ 22? (a) 75 (b) 7500 (c) 750
  8. 8.√82 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 8.8 (d) 9.1
  9. 9.Best estimate of 4816 ÷ 77? (a) 60 (b) 600 (c) 6000
  10. 10.Best estimate of 855 ÷ 32? (a) 2900 (b) 290 (c) 29
  11. 11.Best estimate of 2799 ÷ 36? (a) 7000 (b) 700 (c) 70
  12. 12.Best estimate of 1099 ÷ 29? (a) 37 (b) 370 (c) 3700
  13. 13.√38 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.3 (d) 6.4
  14. 14.Best estimate of 545 ÷ 32? (a) 18 (b) 180 (c) 1800
  15. 15.√77 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 9.0 (d) 9.1
  16. 16.√58 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.9 (d) 7.7
  17. 17.√55 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.2
  18. 18.√44 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.5
  19. 19.Best estimate of 4350 ÷ 86? (a) 480 (b) 48 (c) 4800
  20. 20.Best estimate of 1361 ÷ 27? (a) 450 (b) 45 (c) 4500
  21. 21.√74 to 1 decimal place? (a) 8.3 (b) 8.6 (c) 8.4 (d) 8.5
  22. 22.Best estimate of 2300 ÷ 41? (a) 5800 (b) 580 (c) 58
  23. 23.√28 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.3
  24. 24.√29 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.3 (d) 5.4
  25. 25.Best estimate of 2282 ÷ 59? (a) 38 (b) 3800 (c) 380
  26. 26.Best estimate of 5186 ÷ 69? (a) 740 (b) 7400 (c) 74
  27. 27.Best estimate of 4302 ÷ 88? (a) 4800 (b) 48 (c) 480
  28. 28.Best estimate of 832 ÷ 34? (a) 280 (b) 2800 (c) 28
  29. 29.√34 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 6.1 (d) 5.9
  30. 30.Best estimate of 4203 ÷ 82? (a) 530 (b) 53 (c) 5300
  31. 31.Best estimate of 4963 ÷ 54? (a) 990 (b) 9900 (c) 99
  32. 32.√86 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.3 (d) 9.1
  33. 33.Best estimate of 2041 ÷ 82? (a) 26 (b) 260 (c) 2600
  34. 34.Best estimate of 3257 ÷ 48? (a) 650 (b) 6500 (c) 65
  35. 35.Best estimate of 855 ÷ 26? (a) 290 (b) 29 (c) 2900
  36. 36.Best estimate of 4576 ÷ 66? (a) 65 (b) 6500 (c) 650
  37. 37.√70 to 1 decimal place? (a) 8.3 (b) 8.5 (c) 8.4 (d) 8.6
  38. 38.Best estimate of 5625 ÷ 83? (a) 700 (b) 7000 (c) 70
  39. 39.Best estimate of 1608 ÷ 31? (a) 5400 (b) 54 (c) 540
  40. 40.Best estimate of 2223 ÷ 37? (a) 56 (b) 560 (c) 5600

Answer key

  1. 28
  2. 66
  3. 24
  4. 22
  5. 4.8
  6. 73
  7. 75
  8. 9.1
  9. 60
  10. 29
  11. 70
  12. 37
  13. 6.2
  14. 18
  15. 8.8
  16. 7.6
  17. 7.4
  18. 6.6
  19. 48
  20. 45
  21. 8.6
  22. 58
  23. 5.3
  24. 5.4
  25. 38
  26. 74
  27. 48
  28. 28
  29. 5.8
  30. 53
  31. 99
  32. 9.3
  33. 26
  34. 65
  35. 29
  36. 65
  37. 8.4
  38. 70
  39. 54
  40. 56

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