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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 719 · 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 2654 ÷ 87? (a) 2900 (b) 29 (c) 290
  2. 2.√50 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.1 (d) 7.2
  3. 3.Best estimate of 1260 ÷ 52? (a) 25 (b) 2500 (c) 250
  4. 4.Best estimate of 1972 ÷ 24? (a) 990 (b) 99 (c) 9900
  5. 5.Best estimate of 584 ÷ 36? (a) 1500 (b) 150 (c) 15
  6. 6.Best estimate of 603 ÷ 32? (a) 20 (b) 2000 (c) 200
  7. 7.Best estimate of 1343 ÷ 52? (a) 27 (b) 270 (c) 2700
  8. 8.√40 to 1 decimal place? (a) 6.3 (b) 6.2 (c) 6.1 (d) 6.0
  9. 9.Best estimate of 4809 ÷ 88? (a) 5300 (b) 53 (c) 530
  10. 10.Best estimate of 1409 ÷ 79? (a) 180 (b) 1800 (c) 18
  11. 11.Best estimate of 2213 ÷ 33? (a) 740 (b) 7400 (c) 74
  12. 12.√76 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.4 (d) 8.5
  13. 13.Best estimate of 1781 ÷ 36? (a) 4500 (b) 45 (c) 450
  14. 14.Best estimate of 3769 ÷ 56? (a) 6300 (b) 630 (c) 63
  15. 15.Best estimate of 1718 ÷ 81? (a) 2100 (b) 210 (c) 21
  16. 16.Best estimate of 1821 ÷ 21? (a) 910 (b) 9100 (c) 91
  17. 17.Best estimate of 2261 ÷ 72? (a) 3200 (b) 320 (c) 32
  18. 18.√98 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 10.0 (d) 9.9
  19. 19.√26 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.3 (d) 5.4
  20. 20.Best estimate of 3398 ÷ 49? (a) 6800 (b) 68 (c) 680
  21. 21.Best estimate of 2550 ÷ 46? (a) 510 (b) 5100 (c) 51
  22. 22.Best estimate of 390 ÷ 32? (a) 13 (b) 1300 (c) 130
  23. 23.Best estimate of 4004 ÷ 52? (a) 800 (b) 8000 (c) 80
  24. 24.Best estimate of 1781 ÷ 27? (a) 5900 (b) 59 (c) 590
  25. 25.Best estimate of 3227 ÷ 36? (a) 8100 (b) 810 (c) 81
  26. 26.Best estimate of 748 ÷ 59? (a) 12 (b) 120 (c) 1200
  27. 27.Best estimate of 4987 ÷ 76? (a) 6200 (b) 62 (c) 620
  28. 28.Best estimate of 1306 ÷ 89? (a) 150 (b) 1500 (c) 15
  29. 29.√47 to 1 decimal place? (a) 7.0 (b) 6.9 (c) 6.8 (d) 6.7
  30. 30.√61 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 8.1 (d) 8.0
  31. 31.√24 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.9 (d) 5.0
  32. 32.√92 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.5 (d) 9.6
  33. 33.√69 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.5 (d) 8.2
  34. 34.Best estimate of 3133 ÷ 36? (a) 78 (b) 780 (c) 7800
  35. 35.Best estimate of 2480 ÷ 68? (a) 350 (b) 3500 (c) 35
  36. 36.√72 to 1 decimal place? (a) 8.6 (b) 8.7 (c) 8.5 (d) 8.4
  37. 37.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 5.8
  38. 38.Best estimate of 3341 ÷ 44? (a) 8400 (b) 84 (c) 840
  39. 39.Best estimate of 4270 ÷ 87? (a) 4700 (b) 470 (c) 47
  40. 40.√58 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.7 (d) 7.9

Answer key

  1. 29
  2. 7.1
  3. 25
  4. 99
  5. 15
  6. 20
  7. 27
  8. 6.3
  9. 53
  10. 18
  11. 74
  12. 8.7
  13. 45
  14. 63
  15. 21
  16. 91
  17. 32
  18. 9.9
  19. 5.1
  20. 68
  21. 51
  22. 13
  23. 80
  24. 59
  25. 81
  26. 12
  27. 62
  28. 15
  29. 6.9
  30. 7.8
  31. 4.9
  32. 9.6
  33. 8.3
  34. 78
  35. 35
  36. 8.5
  37. 6.1
  38. 84
  39. 47
  40. 7.6

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