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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 571 · 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 2896 ÷ 31? (a) 97 (b) 970 (c) 9700
  2. 2.Best estimate of 3375 ÷ 86? (a) 38 (b) 380 (c) 3800
  3. 3.Best estimate of 4549 ÷ 59? (a) 7600 (b) 760 (c) 76
  4. 4.Best estimate of 2888 ÷ 41? (a) 720 (b) 7200 (c) 72
  5. 5.√65 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.1 (d) 8.4
  6. 6.Best estimate of 664 ÷ 26? (a) 2200 (b) 22 (c) 220
  7. 7.Best estimate of 3854 ÷ 76? (a) 4800 (b) 480 (c) 48
  8. 8.√50 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.8 (d) 7.1
  9. 9.Best estimate of 3144 ÷ 43? (a) 79 (b) 7900 (c) 790
  10. 10.Best estimate of 1820 ÷ 31? (a) 610 (b) 6100 (c) 61
  11. 11.√83 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.4
  12. 12.Best estimate of 1140 ÷ 37? (a) 290 (b) 29 (c) 2900
  13. 13.Best estimate of 1374 ÷ 58? (a) 230 (b) 2300 (c) 23
  14. 14.Best estimate of 3849 ÷ 72? (a) 5500 (b) 55 (c) 550
  15. 15.√40 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.4 (d) 6.5
  16. 16.Best estimate of 2843 ÷ 33? (a) 95 (b) 950 (c) 9500
  17. 17.√51 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 7.2 (d) 6.9
  18. 18.√55 to 1 decimal place? (a) 7.4 (b) 7.1 (c) 7.2 (d) 7.3
  19. 19.√98 to 1 decimal place? (a) 9.9 (b) 10.1 (c) 10.2 (d) 10.0
  20. 20.√47 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.1 (d) 7.0
  21. 21.√37 to 1 decimal place? (a) 6.2 (b) 5.9 (c) 6.1 (d) 6.0
  22. 22.√34 to 1 decimal place? (a) 5.7 (b) 5.8 (c) 5.6 (d) 5.9
  23. 23.√20 to 1 decimal place? (a) 4.6 (b) 4.4 (c) 4.5 (d) 4.7
  24. 24.Best estimate of 3642 ÷ 56? (a) 6100 (b) 610 (c) 61
  25. 25.√26 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.0 (d) 5.2
  26. 26.Best estimate of 706 ÷ 21? (a) 350 (b) 35 (c) 3500
  27. 27.Best estimate of 778 ÷ 23? (a) 390 (b) 39 (c) 3900
  28. 28.Best estimate of 814 ÷ 62? (a) 140 (b) 14 (c) 1400
  29. 29.Best estimate of 3589 ÷ 41? (a) 900 (b) 9000 (c) 90
  30. 30.Best estimate of 1549 ÷ 76? (a) 1900 (b) 190 (c) 19
  31. 31.Best estimate of 5613 ÷ 79? (a) 7000 (b) 700 (c) 70
  32. 32.Best estimate of 933 ÷ 43? (a) 230 (b) 23 (c) 2300
  33. 33.Best estimate of 1887 ÷ 46? (a) 38 (b) 380 (c) 3800
  34. 34.Best estimate of 1664 ÷ 72? (a) 24 (b) 2400 (c) 240
  35. 35.Best estimate of 4968 ÷ 73? (a) 7100 (b) 71 (c) 710
  36. 36.√52 to 1 decimal place? (a) 7.2 (b) 7.1 (c) 7.3 (d) 7.4
  37. 37.√56 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.8
  38. 38.√42 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.8
  39. 39.Best estimate of 642 ÷ 21? (a) 32 (b) 3200 (c) 320
  40. 40.Best estimate of 3854 ÷ 48? (a) 77 (b) 7700 (c) 770

Answer key

  1. 97
  2. 38
  3. 76
  4. 72
  5. 8.1
  6. 22
  7. 48
  8. 7.1
  9. 79
  10. 61
  11. 9.1
  12. 29
  13. 23
  14. 55
  15. 6.3
  16. 95
  17. 7.1
  18. 7.4
  19. 9.9
  20. 6.9
  21. 6.1
  22. 5.8
  23. 4.5
  24. 61
  25. 5.1
  26. 35
  27. 39
  28. 14
  29. 90
  30. 19
  31. 70
  32. 23
  33. 38
  34. 24
  35. 71
  36. 7.2
  37. 7.5
  38. 6.5
  39. 32
  40. 77

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