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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 100 · 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 1206 ÷ 36? (a) 3000 (b) 30 (c) 300
  2. 2.Best estimate of 2547 ÷ 36? (a) 64 (b) 640 (c) 6400
  3. 3.Best estimate of 2123 ÷ 23? (a) 106 (b) 1060 (c) 10600
  4. 4.Best estimate of 2703 ÷ 42? (a) 6800 (b) 68 (c) 680
  5. 5.Best estimate of 737 ÷ 26? (a) 2500 (b) 25 (c) 250
  6. 6.Best estimate of 1677 ÷ 36? (a) 420 (b) 42 (c) 4200
  7. 7.√26 to 1 decimal place? (a) 4.9 (b) 5.1 (c) 5.2 (d) 5.0
  8. 8.Best estimate of 2619 ÷ 39? (a) 65 (b) 6500 (c) 650
  9. 9.√65 to 1 decimal place? (a) 8.0 (b) 7.8 (c) 7.9 (d) 8.1
  10. 10.√88 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.7 (d) 9.6
  11. 11.√58 to 1 decimal place? (a) 7.6 (b) 7.8 (c) 7.7 (d) 7.5
  12. 12.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.4 (d) 9.3
  13. 13.Best estimate of 2967 ÷ 47? (a) 5900 (b) 59 (c) 590
  14. 14.Best estimate of 1191 ÷ 28? (a) 400 (b) 40 (c) 4000
  15. 15.√50 to 1 decimal place? (a) 7.0 (b) 7.1 (c) 7.2 (d) 7.3
  16. 16.Best estimate of 1321 ÷ 72? (a) 1900 (b) 190 (c) 19
  17. 17.√27 to 1 decimal place? (a) 5.4 (b) 5.1 (c) 5.3 (d) 5.2
  18. 18.√40 to 1 decimal place? (a) 6.3 (b) 6.6 (c) 6.5 (d) 6.4
  19. 19.√92 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  20. 20.√67 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.0
  21. 21.Best estimate of 3555 ÷ 72? (a) 51 (b) 5100 (c) 510
  22. 22.√48 to 1 decimal place? (a) 6.8 (b) 6.9 (c) 7.0 (d) 6.7
  23. 23.Best estimate of 1131 ÷ 32? (a) 38 (b) 3800 (c) 380
  24. 24.√69 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 8.3 (d) 8.0
  25. 25.√47 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.0 (d) 6.9
  26. 26.Best estimate of 1009 ÷ 37? (a) 250 (b) 25 (c) 2500
  27. 27.Best estimate of 1938 ÷ 51? (a) 39 (b) 3900 (c) 390
  28. 28.Best estimate of 1147 ÷ 59? (a) 19 (b) 190 (c) 1900
  29. 29.Best estimate of 3666 ÷ 76? (a) 4600 (b) 46 (c) 460
  30. 30.Best estimate of 2315 ÷ 56? (a) 39 (b) 3900 (c) 390
  31. 31.Best estimate of 3628 ÷ 41? (a) 9100 (b) 910 (c) 91
  32. 32.√62 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.9 (d) 8.0
  33. 33.Best estimate of 4299 ÷ 52? (a) 8600 (b) 860 (c) 86
  34. 34.Best estimate of 2818 ÷ 34? (a) 940 (b) 94 (c) 9400
  35. 35.Best estimate of 4712 ÷ 71? (a) 67 (b) 6700 (c) 670
  36. 36.√34 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 6.0 (d) 5.8
  37. 37.Best estimate of 6023 ÷ 88? (a) 6700 (b) 670 (c) 67
  38. 38.√43 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.7 (d) 6.5
  39. 39.√24 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.0 (d) 4.9
  40. 40.Best estimate of 982 ÷ 74? (a) 140 (b) 14 (c) 1400

Answer key

  1. 30
  2. 64
  3. 106
  4. 68
  5. 25
  6. 42
  7. 5.1
  8. 65
  9. 8.1
  10. 9.4
  11. 7.6
  12. 9.1
  13. 59
  14. 40
  15. 7.1
  16. 19
  17. 5.2
  18. 6.3
  19. 9.6
  20. 8.2
  21. 51
  22. 6.9
  23. 38
  24. 8.3
  25. 6.9
  26. 25
  27. 39
  28. 19
  29. 46
  30. 39
  31. 91
  32. 7.9
  33. 86
  34. 94
  35. 67
  36. 5.8
  37. 67
  38. 6.6
  39. 4.9
  40. 14

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