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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 833 · 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 3205 ÷ 59? (a) 5300 (b) 53 (c) 530
  2. 2.√58 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.6 (d) 7.7
  3. 3.√27 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 5.2 (d) 5.1
  4. 4.√26 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.3 (d) 5.4
  5. 5.Best estimate of 1270 ÷ 89? (a) 1400 (b) 14 (c) 140
  6. 6.Best estimate of 3568 ÷ 49? (a) 71 (b) 7100 (c) 710
  7. 7.√80 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.8 (d) 8.7
  8. 8.Best estimate of 1015 ÷ 67? (a) 15 (b) 1500 (c) 150
  9. 9.Best estimate of 684 ÷ 26? (a) 230 (b) 2300 (c) 23
  10. 10.Best estimate of 1608 ÷ 62? (a) 270 (b) 27 (c) 2700
  11. 11.√42 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.3 (d) 6.2
  12. 12.Best estimate of 1491 ÷ 37? (a) 37 (b) 3700 (c) 370
  13. 13.√89 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.5
  14. 14.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  15. 15.√34 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.8 (d) 5.7
  16. 16.√94 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.8 (d) 9.5
  17. 17.Best estimate of 393 ÷ 32? (a) 130 (b) 1300 (c) 13
  18. 18.√47 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.7 (d) 6.8
  19. 19.Best estimate of 2538 ÷ 62? (a) 4200 (b) 42 (c) 420
  20. 20.Best estimate of 358 ÷ 21? (a) 18 (b) 180 (c) 1800
  21. 21.Best estimate of 2229 ÷ 52? (a) 450 (b) 4500 (c) 45
  22. 22.Best estimate of 3857 ÷ 59? (a) 640 (b) 64 (c) 6400
  23. 23.Best estimate of 3903 ÷ 42? (a) 980 (b) 98 (c) 9800
  24. 24.Best estimate of 3745 ÷ 41? (a) 9400 (b) 940 (c) 94
  25. 25.Best estimate of 1969 ÷ 52? (a) 3900 (b) 39 (c) 390
  26. 26.Best estimate of 3736 ÷ 66? (a) 530 (b) 53 (c) 5300
  27. 27.Best estimate of 3730 ÷ 61? (a) 620 (b) 62 (c) 6200
  28. 28.Best estimate of 1443 ÷ 77? (a) 180 (b) 1800 (c) 18
  29. 29.Best estimate of 1385 ÷ 39? (a) 350 (b) 35 (c) 3500
  30. 30.Best estimate of 3544 ÷ 56? (a) 590 (b) 59 (c) 5900
  31. 31.Best estimate of 3069 ÷ 56? (a) 510 (b) 5100 (c) 51
  32. 32.Best estimate of 2334 ÷ 46? (a) 470 (b) 4700 (c) 47
  33. 33.Best estimate of 1457 ÷ 27? (a) 4900 (b) 490 (c) 49
  34. 34.Best estimate of 2029 ÷ 76? (a) 250 (b) 25 (c) 2500
  35. 35.Best estimate of 4790 ÷ 63? (a) 800 (b) 8000 (c) 80
  36. 36.√63 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 8.2
  37. 37.√96 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.7 (d) 9.8
  38. 38.Best estimate of 604 ÷ 26? (a) 200 (b) 20 (c) 2000
  39. 39.Best estimate of 865 ÷ 28? (a) 290 (b) 29 (c) 2900
  40. 40.√98 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.9

Answer key

  1. 53
  2. 7.6
  3. 5.2
  4. 5.1
  5. 14
  6. 71
  7. 8.9
  8. 15
  9. 23
  10. 27
  11. 6.5
  12. 37
  13. 9.4
  14. 7.8
  15. 5.8
  16. 9.7
  17. 13
  18. 6.9
  19. 42
  20. 18
  21. 45
  22. 64
  23. 98
  24. 94
  25. 39
  26. 53
  27. 62
  28. 18
  29. 35
  30. 59
  31. 51
  32. 47
  33. 49
  34. 25
  35. 80
  36. 7.9
  37. 9.8
  38. 20
  39. 29
  40. 9.9

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