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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 466 · 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.√96 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.6 (d) 9.8
  2. 2.√48 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 6.6
  3. 3.√69 to 1 decimal place? (a) 8.3 (b) 8.0 (c) 8.2 (d) 8.1
  4. 4.Best estimate of 1810 ÷ 72? (a) 260 (b) 2600 (c) 26
  5. 5.Best estimate of 4436 ÷ 84? (a) 550 (b) 5500 (c) 55
  6. 6.√90 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.5
  7. 7.Best estimate of 3606 ÷ 52? (a) 7200 (b) 72 (c) 720
  8. 8.Best estimate of 368 ÷ 21? (a) 18 (b) 1800 (c) 180
  9. 9.Best estimate of 1560 ÷ 27? (a) 5200 (b) 52 (c) 520
  10. 10.Best estimate of 4703 ÷ 57? (a) 78 (b) 7800 (c) 780
  11. 11.√24 to 1 decimal place? (a) 4.7 (b) 5.0 (c) 4.9 (d) 4.8
  12. 12.√75 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  13. 13.√26 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 5.0 (d) 5.1
  14. 14.Best estimate of 2741 ÷ 54? (a) 5500 (b) 55 (c) 550
  15. 15.√84 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.3 (d) 9.1
  16. 16.√41 to 1 decimal place? (a) 6.2 (b) 6.5 (c) 6.4 (d) 6.3
  17. 17.Best estimate of 2098 ÷ 69? (a) 3000 (b) 30 (c) 300
  18. 18.Best estimate of 1743 ÷ 46? (a) 35 (b) 3500 (c) 350
  19. 19.Best estimate of 5038 ÷ 67? (a) 720 (b) 7200 (c) 72
  20. 20.Best estimate of 3447 ÷ 49? (a) 690 (b) 6900 (c) 69
  21. 21.√28 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 5.3 (d) 5.1
  22. 22.Best estimate of 5403 ÷ 83? (a) 680 (b) 68 (c) 6800
  23. 23.√37 to 1 decimal place? (a) 6.1 (b) 6.3 (c) 6.0 (d) 6.2
  24. 24.Best estimate of 1246 ÷ 74? (a) 18 (b) 1800 (c) 180
  25. 25.√62 to 1 decimal place? (a) 8.1 (b) 8.0 (c) 7.9 (d) 8.2
  26. 26.Best estimate of 4216 ÷ 57? (a) 700 (b) 70 (c) 7000
  27. 27.Best estimate of 1525 ÷ 67? (a) 220 (b) 22 (c) 2200
  28. 28.√94 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.9 (d) 9.6
  29. 29.Best estimate of 1540 ÷ 56? (a) 26 (b) 260 (c) 2600
  30. 30.Best estimate of 1726 ÷ 21? (a) 860 (b) 8600 (c) 86
  31. 31.√88 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.4 (d) 9.5
  32. 32.√32 to 1 decimal place? (a) 5.7 (b) 6.0 (c) 5.9 (d) 5.8
  33. 33.Best estimate of 1836 ÷ 39? (a) 460 (b) 4600 (c) 46
  34. 34.Best estimate of 4365 ÷ 81? (a) 550 (b) 55 (c) 5500
  35. 35.√43 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.7 (d) 6.5
  36. 36.√98 to 1 decimal place? (a) 10.0 (b) 10.2 (c) 10.1 (d) 9.9
  37. 37.√86 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.6
  38. 38.√30 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.8 (d) 5.7
  39. 39.√42 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.3 (d) 6.6
  40. 40.Best estimate of 324 ÷ 26? (a) 110 (b) 1100 (c) 11

Answer key

  1. 9.8
  2. 6.9
  3. 8.3
  4. 26
  5. 55
  6. 9.5
  7. 72
  8. 18
  9. 52
  10. 78
  11. 4.9
  12. 8.7
  13. 5.1
  14. 55
  15. 9.2
  16. 6.4
  17. 30
  18. 35
  19. 72
  20. 69
  21. 5.3
  22. 68
  23. 6.1
  24. 18
  25. 7.9
  26. 70
  27. 22
  28. 9.7
  29. 26
  30. 86
  31. 9.4
  32. 5.7
  33. 46
  34. 55
  35. 6.6
  36. 9.9
  37. 9.3
  38. 5.5
  39. 6.5
  40. 11

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