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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 649 · 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 1147 ÷ 81? (a) 140 (b) 14 (c) 1400
  2. 2.Best estimate of 5965 ÷ 89? (a) 660 (b) 6600 (c) 66
  3. 3.Best estimate of 2033 ÷ 39? (a) 5100 (b) 51 (c) 510
  4. 4.Best estimate of 1364 ÷ 49? (a) 270 (b) 27 (c) 2700
  5. 5.√34 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.9 (d) 6.0
  6. 6.√47 to 1 decimal place? (a) 7.0 (b) 6.8 (c) 6.9 (d) 7.1
  7. 7.Best estimate of 978 ÷ 63? (a) 160 (b) 1600 (c) 16
  8. 8.Best estimate of 2558 ÷ 27? (a) 8500 (b) 85 (c) 850
  9. 9.Best estimate of 3502 ÷ 42? (a) 880 (b) 88 (c) 8800
  10. 10.Best estimate of 1780 ÷ 73? (a) 250 (b) 2500 (c) 25
  11. 11.Best estimate of 3588 ÷ 49? (a) 7200 (b) 72 (c) 720
  12. 12.√42 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.4 (d) 6.6
  13. 13.√71 to 1 decimal place? (a) 8.6 (b) 8.3 (c) 8.4 (d) 8.5
  14. 14.Best estimate of 5248 ÷ 71? (a) 750 (b) 75 (c) 7500
  15. 15.√31 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.5 (d) 5.8
  16. 16.Best estimate of 1659 ÷ 71? (a) 2400 (b) 240 (c) 24
  17. 17.√80 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 8.8
  18. 18.√55 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.1 (d) 7.3
  19. 19.Best estimate of 1036 ÷ 33? (a) 3500 (b) 350 (c) 35
  20. 20.√69 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.4 (d) 8.3
  21. 21.Best estimate of 1134 ÷ 29? (a) 38 (b) 3800 (c) 380
  22. 22.Best estimate of 882 ÷ 26? (a) 290 (b) 29 (c) 2900
  23. 23.Best estimate of 816 ÷ 42? (a) 2000 (b) 20 (c) 200
  24. 24.√51 to 1 decimal place? (a) 7.2 (b) 7.4 (c) 7.1 (d) 7.3
  25. 25.Best estimate of 5630 ÷ 76? (a) 700 (b) 7000 (c) 70
  26. 26.Best estimate of 4420 ÷ 64? (a) 740 (b) 7400 (c) 74
  27. 27.√87 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.2 (d) 9.1
  28. 28.Best estimate of 941 ÷ 64? (a) 16 (b) 160 (c) 1600
  29. 29.√41 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.3 (d) 6.5
  30. 30.Best estimate of 1763 ÷ 36? (a) 44 (b) 4400 (c) 440
  31. 31.Best estimate of 3449 ÷ 87? (a) 3800 (b) 38 (c) 380
  32. 32.Best estimate of 2133 ÷ 82? (a) 270 (b) 27 (c) 2700
  33. 33.√29 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.6 (d) 5.5
  34. 34.Best estimate of 3779 ÷ 52? (a) 760 (b) 7600 (c) 76
  35. 35.√28 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.6 (d) 5.4
  36. 36.Best estimate of 1965 ÷ 46? (a) 390 (b) 39 (c) 3900
  37. 37.√89 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.1
  38. 38.Best estimate of 1462 ÷ 73? (a) 21 (b) 2100 (c) 210
  39. 39.Best estimate of 2909 ÷ 39? (a) 730 (b) 73 (c) 7300
  40. 40.Best estimate of 3620 ÷ 42? (a) 91 (b) 9100 (c) 910

Answer key

  1. 14
  2. 66
  3. 51
  4. 27
  5. 5.8
  6. 6.9
  7. 16
  8. 85
  9. 88
  10. 25
  11. 72
  12. 6.5
  13. 8.4
  14. 75
  15. 5.6
  16. 24
  17. 8.9
  18. 7.4
  19. 35
  20. 8.3
  21. 38
  22. 29
  23. 20
  24. 7.1
  25. 70
  26. 74
  27. 9.3
  28. 16
  29. 6.4
  30. 44
  31. 38
  32. 27
  33. 5.4
  34. 76
  35. 5.3
  36. 39
  37. 9.4
  38. 21
  39. 73
  40. 91

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