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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 223 · 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 1377 ÷ 62? (a) 2300 (b) 23 (c) 230
  2. 2.√23 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.9 (d) 4.8
  3. 3.Best estimate of 4666 ÷ 58? (a) 7800 (b) 780 (c) 78
  4. 4.Best estimate of 2378 ÷ 42? (a) 5900 (b) 59 (c) 590
  5. 5.Best estimate of 1726 ÷ 23? (a) 8600 (b) 86 (c) 860
  6. 6.√50 to 1 decimal place? (a) 7.1 (b) 7.0 (c) 7.3 (d) 7.2
  7. 7.√65 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.3 (d) 8.1
  8. 8.√89 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.2 (d) 9.1
  9. 9.√38 to 1 decimal place? (a) 6.4 (b) 6.2 (c) 6.5 (d) 6.3
  10. 10.Best estimate of 612 ÷ 28? (a) 2000 (b) 20 (c) 200
  11. 11.Best estimate of 568 ÷ 39? (a) 1400 (b) 14 (c) 140
  12. 12.√37 to 1 decimal place? (a) 6.2 (b) 6.0 (c) 5.9 (d) 6.1
  13. 13.√42 to 1 decimal place? (a) 6.7 (b) 6.5 (c) 6.6 (d) 6.8
  14. 14.√40 to 1 decimal place? (a) 6.1 (b) 6.4 (c) 6.3 (d) 6.2
  15. 15.Best estimate of 5896 ÷ 73? (a) 84 (b) 840 (c) 8400
  16. 16.Best estimate of 1037 ÷ 26? (a) 350 (b) 3500 (c) 35
  17. 17.Best estimate of 2345 ÷ 76? (a) 29 (b) 2900 (c) 290
  18. 18.Best estimate of 2636 ÷ 42? (a) 660 (b) 66 (c) 6600
  19. 19.√58 to 1 decimal place? (a) 7.7 (b) 7.5 (c) 7.8 (d) 7.6
  20. 20.Best estimate of 2668 ÷ 76? (a) 330 (b) 33 (c) 3300
  21. 21.Best estimate of 1949 ÷ 42? (a) 4900 (b) 49 (c) 490
  22. 22.Best estimate of 5045 ÷ 72? (a) 720 (b) 72 (c) 7200
  23. 23.Best estimate of 1270 ÷ 51? (a) 2500 (b) 250 (c) 25
  24. 24.√94 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.7 (d) 9.5
  25. 25.Best estimate of 759 ÷ 27? (a) 250 (b) 2500 (c) 25
  26. 26.√29 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.7
  27. 27.Best estimate of 2176 ÷ 79? (a) 270 (b) 27 (c) 2700
  28. 28.Best estimate of 1586 ÷ 33? (a) 530 (b) 53 (c) 5300
  29. 29.√80 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.7 (d) 8.8
  30. 30.Best estimate of 6088 ÷ 64? (a) 10100 (b) 101 (c) 1010
  31. 31.Best estimate of 739 ÷ 29? (a) 250 (b) 2500 (c) 25
  32. 32.√78 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.8
  33. 33.Best estimate of 2290 ÷ 28? (a) 76 (b) 7600 (c) 760
  34. 34.Best estimate of 3770 ÷ 43? (a) 94 (b) 9400 (c) 940
  35. 35.Best estimate of 1511 ÷ 39? (a) 38 (b) 3800 (c) 380
  36. 36.Best estimate of 1539 ÷ 48? (a) 31 (b) 310 (c) 3100
  37. 37.Best estimate of 2620 ÷ 52? (a) 52 (b) 5200 (c) 520
  38. 38.√62 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.8 (d) 7.6
  39. 39.Best estimate of 2310 ÷ 53? (a) 4600 (b) 46 (c) 460
  40. 40.Best estimate of 1719 ÷ 29? (a) 570 (b) 5700 (c) 57

Answer key

  1. 23
  2. 4.8
  3. 78
  4. 59
  5. 86
  6. 7.1
  7. 8.1
  8. 9.4
  9. 6.2
  10. 20
  11. 14
  12. 6.1
  13. 6.5
  14. 6.3
  15. 84
  16. 35
  17. 29
  18. 66
  19. 7.6
  20. 33
  21. 49
  22. 72
  23. 25
  24. 9.7
  25. 25
  26. 5.4
  27. 27
  28. 53
  29. 8.9
  30. 101
  31. 25
  32. 8.8
  33. 76
  34. 94
  35. 38
  36. 31
  37. 52
  38. 7.9
  39. 46
  40. 57

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