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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 231 · 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 3562 ÷ 62? (a) 59 (b) 590 (c) 5900
  2. 2.Best estimate of 2601 ÷ 52? (a) 52 (b) 5200 (c) 520
  3. 3.√38 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 6.2
  4. 4.Best estimate of 952 ÷ 67? (a) 14 (b) 1400 (c) 140
  5. 5.Best estimate of 3316 ÷ 89? (a) 370 (b) 3700 (c) 37
  6. 6.Best estimate of 2517 ÷ 29? (a) 8400 (b) 840 (c) 84
  7. 7.√35 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 6.0 (d) 5.8
  8. 8.√50 to 1 decimal place? (a) 7.1 (b) 7.3 (c) 7.2 (d) 7.4
  9. 9.√20 to 1 decimal place? (a) 4.4 (b) 4.3 (c) 4.2 (d) 4.5
  10. 10.Best estimate of 1453 ÷ 71? (a) 2100 (b) 21 (c) 210
  11. 11.Best estimate of 1614 ÷ 41? (a) 400 (b) 4000 (c) 40
  12. 12.√23 to 1 decimal place? (a) 4.9 (b) 4.6 (c) 4.7 (d) 4.8
  13. 13.√86 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.1 (d) 9.2
  14. 14.√29 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.2 (d) 5.4
  15. 15.Best estimate of 2079 ÷ 26? (a) 690 (b) 69 (c) 6900
  16. 16.Best estimate of 1853 ÷ 32? (a) 6200 (b) 620 (c) 62
  17. 17.Best estimate of 1743 ÷ 39? (a) 440 (b) 44 (c) 4400
  18. 18.√92 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.8 (d) 9.6
  19. 19.Best estimate of 1027 ÷ 73? (a) 150 (b) 1500 (c) 15
  20. 20.√58 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.5 (d) 7.8
  21. 21.Best estimate of 3068 ÷ 36? (a) 7700 (b) 770 (c) 77
  22. 22.Best estimate of 1177 ÷ 42? (a) 29 (b) 290 (c) 2900
  23. 23.Best estimate of 4848 ÷ 86? (a) 54 (b) 540 (c) 5400
  24. 24.Best estimate of 1236 ÷ 51? (a) 25 (b) 250 (c) 2500
  25. 25.√46 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.6 (d) 6.8
  26. 26.√32 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 5.7
  27. 27.Best estimate of 1928 ÷ 32? (a) 6400 (b) 640 (c) 64
  28. 28.Best estimate of 4543 ÷ 76? (a) 57 (b) 570 (c) 5700
  29. 29.√56 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.5 (d) 7.4
  30. 30.Best estimate of 7420 ÷ 86? (a) 82 (b) 8200 (c) 820
  31. 31.Best estimate of 4597 ÷ 66? (a) 6600 (b) 66 (c) 660
  32. 32.Best estimate of 2361 ÷ 42? (a) 590 (b) 5900 (c) 59
  33. 33.√94 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.6 (d) 9.7
  34. 34.√44 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 6.6 (d) 6.7
  35. 35.√31 to 1 decimal place? (a) 5.3 (b) 5.6 (c) 5.5 (d) 5.4
  36. 36.Best estimate of 1307 ÷ 31? (a) 44 (b) 4400 (c) 440
  37. 37.Best estimate of 2090 ÷ 47? (a) 420 (b) 4200 (c) 42
  38. 38.√34 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 5.7
  39. 39.Best estimate of 3050 ÷ 48? (a) 6100 (b) 61 (c) 610
  40. 40.Best estimate of 1681 ÷ 44? (a) 42 (b) 4200 (c) 420

Answer key

  1. 59
  2. 52
  3. 6.2
  4. 14
  5. 37
  6. 84
  7. 5.9
  8. 7.1
  9. 4.5
  10. 21
  11. 40
  12. 4.8
  13. 9.3
  14. 5.4
  15. 69
  16. 62
  17. 44
  18. 9.6
  19. 15
  20. 7.6
  21. 77
  22. 29
  23. 54
  24. 25
  25. 6.8
  26. 5.7
  27. 64
  28. 57
  29. 7.5
  30. 82
  31. 66
  32. 59
  33. 9.7
  34. 6.6
  35. 5.6
  36. 44
  37. 42
  38. 5.8
  39. 61
  40. 42

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