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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 50 · 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 3838 ÷ 53? (a) 77 (b) 770 (c) 7700
  2. 2.√75 to 1 decimal place? (a) 8.5 (b) 8.8 (c) 8.7 (d) 8.6
  3. 3.Best estimate of 3255 ÷ 49? (a) 6500 (b) 65 (c) 650
  4. 4.Best estimate of 587 ÷ 36? (a) 1500 (b) 15 (c) 150
  5. 5.√26 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 5.1 (d) 4.8
  6. 6.Best estimate of 1880 ÷ 32? (a) 630 (b) 6300 (c) 63
  7. 7.Best estimate of 3942 ÷ 61? (a) 66 (b) 6600 (c) 660
  8. 8.Best estimate of 940 ÷ 72? (a) 13 (b) 1300 (c) 130
  9. 9.Best estimate of 1696 ÷ 53? (a) 3400 (b) 34 (c) 340
  10. 10.√63 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 8.0 (d) 7.9
  11. 11.Best estimate of 502 ÷ 27? (a) 1700 (b) 170 (c) 17
  12. 12.Best estimate of 1348 ÷ 23? (a) 67 (b) 670 (c) 6700
  13. 13.√92 to 1 decimal place? (a) 9.7 (b) 9.5 (c) 9.6 (d) 9.8
  14. 14.√32 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 5.7
  15. 15.Best estimate of 652 ÷ 26? (a) 2200 (b) 22 (c) 220
  16. 16.√72 to 1 decimal place? (a) 8.2 (b) 8.3 (c) 8.5 (d) 8.4
  17. 17.Best estimate of 1656 ÷ 56? (a) 2800 (b) 28 (c) 280
  18. 18.√85 to 1 decimal place? (a) 9.3 (b) 9.1 (c) 9.2 (d) 9.4
  19. 19.Best estimate of 1502 ÷ 64? (a) 25 (b) 2500 (c) 250
  20. 20.√40 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.2 (d) 6.1
  21. 21.Best estimate of 542 ÷ 28? (a) 1800 (b) 180 (c) 18
  22. 22.Best estimate of 3641 ÷ 72? (a) 5200 (b) 52 (c) 520
  23. 23.√67 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.4 (d) 8.1
  24. 24.√56 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.6 (d) 7.8
  25. 25.√74 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.3 (d) 8.5
  26. 26.√53 to 1 decimal place? (a) 7.1 (b) 7.2 (c) 7.3 (d) 7.0
  27. 27.Best estimate of 598 ÷ 32? (a) 2000 (b) 20 (c) 200
  28. 28.√50 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.1 (d) 7.3
  29. 29.√23 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.7 (d) 4.6
  30. 30.Best estimate of 768 ÷ 61? (a) 13 (b) 1300 (c) 130
  31. 31.Best estimate of 3576 ÷ 72? (a) 5100 (b) 51 (c) 510
  32. 32.√96 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.7 (d) 9.8
  33. 33.Best estimate of 5932 ÷ 66? (a) 8500 (b) 850 (c) 85
  34. 34.Best estimate of 1530 ÷ 72? (a) 2200 (b) 220 (c) 22
  35. 35.Best estimate of 3197 ÷ 41? (a) 80 (b) 8000 (c) 800
  36. 36.Best estimate of 771 ÷ 33? (a) 2600 (b) 26 (c) 260
  37. 37.Best estimate of 1716 ÷ 88? (a) 19 (b) 1900 (c) 190
  38. 38.Best estimate of 2020 ÷ 27? (a) 67 (b) 670 (c) 6700
  39. 39.Best estimate of 3735 ÷ 86? (a) 4200 (b) 42 (c) 420
  40. 40.√29 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.3 (d) 5.4

Answer key

  1. 77
  2. 8.7
  3. 65
  4. 15
  5. 5.1
  6. 63
  7. 66
  8. 13
  9. 34
  10. 7.9
  11. 17
  12. 67
  13. 9.6
  14. 5.7
  15. 22
  16. 8.5
  17. 28
  18. 9.2
  19. 25
  20. 6.3
  21. 18
  22. 52
  23. 8.2
  24. 7.5
  25. 8.6
  26. 7.3
  27. 20
  28. 7.1
  29. 4.8
  30. 13
  31. 51
  32. 9.8
  33. 85
  34. 22
  35. 80
  36. 26
  37. 19
  38. 67
  39. 42
  40. 5.4

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