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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 676 · 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.√96 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  2. 2.Best estimate of 2385 ÷ 34? (a) 8000 (b) 80 (c) 800
  3. 3.Best estimate of 1188 ÷ 46? (a) 2400 (b) 240 (c) 24
  4. 4.Best estimate of 3197 ÷ 46? (a) 640 (b) 64 (c) 6400
  5. 5.√71 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.1 (d) 8.4
  6. 6.Best estimate of 954 ÷ 21? (a) 480 (b) 48 (c) 4800
  7. 7.Best estimate of 6488 ÷ 76? (a) 8100 (b) 81 (c) 810
  8. 8.√62 to 1 decimal place? (a) 7.8 (b) 8.1 (c) 7.9 (d) 8.0
  9. 9.Best estimate of 2101 ÷ 22? (a) 105 (b) 1050 (c) 10500
  10. 10.√38 to 1 decimal place? (a) 6.5 (b) 6.2 (c) 6.4 (d) 6.3
  11. 11.√74 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.8 (d) 8.7
  12. 12.Best estimate of 2209 ÷ 49? (a) 4400 (b) 440 (c) 44
  13. 13.Best estimate of 1996 ÷ 88? (a) 220 (b) 2200 (c) 22
  14. 14.√32 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.9 (d) 5.8
  15. 15.√26 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.1 (d) 5.2
  16. 16.Best estimate of 4364 ÷ 46? (a) 87 (b) 8700 (c) 870
  17. 17.Best estimate of 2463 ÷ 72? (a) 350 (b) 35 (c) 3500
  18. 18.Best estimate of 2958 ÷ 77? (a) 370 (b) 37 (c) 3700
  19. 19.√84 to 1 decimal place? (a) 9.2 (b) 9.5 (c) 9.3 (d) 9.4
  20. 20.√58 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.7
  21. 21.Best estimate of 2697 ÷ 67? (a) 390 (b) 39 (c) 3900
  22. 22.Best estimate of 1913 ÷ 46? (a) 380 (b) 38 (c) 3800
  23. 23.√61 to 1 decimal place? (a) 7.9 (b) 7.7 (c) 7.6 (d) 7.8
  24. 24.√92 to 1 decimal place? (a) 9.5 (b) 9.6 (c) 9.7 (d) 9.4
  25. 25.Best estimate of 1904 ÷ 61? (a) 3200 (b) 32 (c) 320
  26. 26.Best estimate of 3286 ÷ 47? (a) 66 (b) 660 (c) 6600
  27. 27.Best estimate of 2894 ÷ 52? (a) 5800 (b) 580 (c) 58
  28. 28.√76 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 9.0 (d) 8.7
  29. 29.Best estimate of 4496 ÷ 82? (a) 5600 (b) 56 (c) 560
  30. 30.√46 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 7.0 (d) 6.8
  31. 31.√65 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.4 (d) 8.1
  32. 32.Best estimate of 2395 ÷ 52? (a) 480 (b) 48 (c) 4800
  33. 33.Best estimate of 4200 ÷ 56? (a) 70 (b) 700 (c) 7000
  34. 34.Best estimate of 1964 ÷ 37? (a) 490 (b) 4900 (c) 49
  35. 35.√82 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.1 (d) 9.4
  36. 36.Best estimate of 4280 ÷ 63? (a) 710 (b) 7100 (c) 71
  37. 37.Best estimate of 644 ÷ 23? (a) 3200 (b) 320 (c) 32
  38. 38.Best estimate of 2612 ÷ 82? (a) 330 (b) 33 (c) 3300
  39. 39.Best estimate of 562 ÷ 36? (a) 1400 (b) 140 (c) 14
  40. 40.√40 to 1 decimal place? (a) 6.5 (b) 6.3 (c) 6.6 (d) 6.4

Answer key

  1. 9.8
  2. 80
  3. 24
  4. 64
  5. 8.4
  6. 48
  7. 81
  8. 7.9
  9. 105
  10. 6.2
  11. 8.6
  12. 44
  13. 22
  14. 5.7
  15. 5.1
  16. 87
  17. 35
  18. 37
  19. 9.2
  20. 7.6
  21. 39
  22. 38
  23. 7.8
  24. 9.6
  25. 32
  26. 66
  27. 58
  28. 8.7
  29. 56
  30. 6.8
  31. 8.1
  32. 48
  33. 70
  34. 49
  35. 9.1
  36. 71
  37. 32
  38. 33
  39. 14
  40. 6.3

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