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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 671 · 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.√40 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.4 (d) 6.5
  2. 2.Best estimate of 1106 ÷ 68? (a) 160 (b) 1600 (c) 16
  3. 3.√86 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.4
  4. 4.√70 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.5 (d) 8.4
  5. 5.Best estimate of 1010 ÷ 29? (a) 34 (b) 3400 (c) 340
  6. 6.Best estimate of 6651 ÷ 86? (a) 740 (b) 7400 (c) 74
  7. 7.√26 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.0 (d) 5.1
  8. 8.√63 to 1 decimal place? (a) 8.0 (b) 7.7 (c) 7.9 (d) 7.8
  9. 9.√43 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.4 (d) 6.3
  10. 10.√53 to 1 decimal place? (a) 7.2 (b) 7.5 (c) 7.3 (d) 7.4
  11. 11.Best estimate of 1871 ÷ 76? (a) 2300 (b) 23 (c) 230
  12. 12.Best estimate of 2116 ÷ 29? (a) 710 (b) 7100 (c) 71
  13. 13.Best estimate of 6398 ÷ 69? (a) 91 (b) 9100 (c) 910
  14. 14.√37 to 1 decimal place? (a) 6.2 (b) 5.9 (c) 6.1 (d) 6.0
  15. 15.Best estimate of 552 ÷ 22? (a) 28 (b) 2800 (c) 280
  16. 16.Best estimate of 2435 ÷ 27? (a) 81 (b) 810 (c) 8100
  17. 17.Best estimate of 1297 ÷ 43? (a) 320 (b) 3200 (c) 32
  18. 18.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.0 (d) 9.2
  19. 19.Best estimate of 1177 ÷ 27? (a) 390 (b) 3900 (c) 39
  20. 20.Best estimate of 3058 ÷ 51? (a) 6100 (b) 61 (c) 610
  21. 21.Best estimate of 1954 ÷ 41? (a) 490 (b) 49 (c) 4900
  22. 22.Best estimate of 4368 ÷ 68? (a) 620 (b) 6200 (c) 62
  23. 23.Best estimate of 2324 ÷ 86? (a) 26 (b) 2600 (c) 260
  24. 24.Best estimate of 5618 ÷ 77? (a) 700 (b) 7000 (c) 70
  25. 25.√35 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 6.0 (d) 5.7
  26. 26.√46 to 1 decimal place? (a) 6.9 (b) 6.7 (c) 6.6 (d) 6.8
  27. 27.Best estimate of 2462 ÷ 27? (a) 820 (b) 8200 (c) 82
  28. 28.Best estimate of 6684 ÷ 79? (a) 840 (b) 8400 (c) 84
  29. 29.√30 to 1 decimal place? (a) 5.4 (b) 5.7 (c) 5.5 (d) 5.6
  30. 30.√21 to 1 decimal place? (a) 4.6 (b) 4.8 (c) 4.5 (d) 4.7
  31. 31.Best estimate of 1034 ÷ 21? (a) 52 (b) 5200 (c) 520
  32. 32.Best estimate of 6604 ÷ 71? (a) 9400 (b) 94 (c) 940
  33. 33.√34 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 5.7 (d) 6.0
  34. 34.√83 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.4
  35. 35.√32 to 1 decimal place? (a) 5.6 (b) 5.4 (c) 5.5 (d) 5.7
  36. 36.√42 to 1 decimal place? (a) 6.6 (b) 6.3 (c) 6.5 (d) 6.4
  37. 37.√38 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.4 (d) 6.1
  38. 38.Best estimate of 3845 ÷ 46? (a) 7700 (b) 77 (c) 770
  39. 39.Best estimate of 1802 ÷ 49? (a) 3600 (b) 360 (c) 36
  40. 40.Best estimate of 2538 ÷ 49? (a) 510 (b) 51 (c) 5100

Answer key

  1. 6.3
  2. 16
  3. 9.3
  4. 8.4
  5. 34
  6. 74
  7. 5.1
  8. 7.9
  9. 6.6
  10. 7.3
  11. 23
  12. 71
  13. 91
  14. 6.1
  15. 28
  16. 81
  17. 32
  18. 9.1
  19. 39
  20. 61
  21. 49
  22. 62
  23. 26
  24. 70
  25. 5.9
  26. 6.8
  27. 82
  28. 84
  29. 5.5
  30. 4.6
  31. 52
  32. 94
  33. 5.8
  34. 9.1
  35. 5.7
  36. 6.5
  37. 6.2
  38. 77
  39. 36
  40. 51

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