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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 200 · 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.√37 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 5.9 (d) 6.2
  2. 2.Best estimate of 1106 ÷ 23? (a) 550 (b) 5500 (c) 55
  3. 3.Best estimate of 3248 ÷ 39? (a) 81 (b) 810 (c) 8100
  4. 4.Best estimate of 4767 ÷ 52? (a) 9500 (b) 95 (c) 950
  5. 5.Best estimate of 4226 ÷ 68? (a) 6000 (b) 60 (c) 600
  6. 6.√55 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.3 (d) 7.5
  7. 7.Best estimate of 4230 ÷ 52? (a) 850 (b) 85 (c) 8500
  8. 8.Best estimate of 3335 ÷ 79? (a) 4200 (b) 42 (c) 420
  9. 9.Best estimate of 2433 ÷ 52? (a) 490 (b) 49 (c) 4900
  10. 10.Best estimate of 3420 ÷ 88? (a) 380 (b) 38 (c) 3800
  11. 11.Best estimate of 2475 ÷ 42? (a) 620 (b) 62 (c) 6200
  12. 12.√26 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 5.1 (d) 5.2
  13. 13.Best estimate of 3902 ÷ 62? (a) 6500 (b) 65 (c) 650
  14. 14.√45 to 1 decimal place? (a) 6.5 (b) 6.7 (c) 6.4 (d) 6.6
  15. 15.√90 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.2 (d) 9.3
  16. 16.Best estimate of 568 ÷ 36? (a) 140 (b) 14 (c) 1400
  17. 17.Best estimate of 2288 ÷ 26? (a) 76 (b) 7600 (c) 760
  18. 18.Best estimate of 476 ÷ 24? (a) 240 (b) 24 (c) 2400
  19. 19.Best estimate of 2393 ÷ 66? (a) 34 (b) 340 (c) 3400
  20. 20.Best estimate of 1354 ÷ 62? (a) 23 (b) 2300 (c) 230
  21. 21.Best estimate of 3220 ÷ 66? (a) 4600 (b) 46 (c) 460
  22. 22.Best estimate of 1999 ÷ 33? (a) 67 (b) 670 (c) 6700
  23. 23.Best estimate of 6890 ÷ 81? (a) 86 (b) 860 (c) 8600
  24. 24.Best estimate of 512 ÷ 32? (a) 1700 (b) 170 (c) 17
  25. 25.√21 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.6 (d) 4.7
  26. 26.Best estimate of 3072 ÷ 52? (a) 610 (b) 6100 (c) 61
  27. 27.√42 to 1 decimal place? (a) 6.4 (b) 6.6 (c) 6.5 (d) 6.3
  28. 28.√98 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 10.1 (d) 9.8
  29. 29.Best estimate of 3687 ÷ 54? (a) 7400 (b) 740 (c) 74
  30. 30.Best estimate of 2652 ÷ 39? (a) 6600 (b) 660 (c) 66
  31. 31.√83 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 9.1 (d) 8.9
  32. 32.Best estimate of 1377 ÷ 32? (a) 4600 (b) 460 (c) 46
  33. 33.Best estimate of 6900 ÷ 83? (a) 8600 (b) 86 (c) 860
  34. 34.Best estimate of 1447 ÷ 56? (a) 2400 (b) 240 (c) 24
  35. 35.√40 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.1 (d) 6.0
  36. 36.Best estimate of 1608 ÷ 26? (a) 540 (b) 5400 (c) 54
  37. 37.√61 to 1 decimal place? (a) 8.0 (b) 7.8 (c) 7.9 (d) 8.1
  38. 38.Best estimate of 5621 ÷ 84? (a) 7000 (b) 70 (c) 700
  39. 39.√27 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.2 (d) 5.4
  40. 40.√29 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.4 (d) 5.7

Answer key

  1. 6.1
  2. 55
  3. 81
  4. 95
  5. 60
  6. 7.4
  7. 85
  8. 42
  9. 49
  10. 38
  11. 62
  12. 5.1
  13. 65
  14. 6.7
  15. 9.5
  16. 14
  17. 76
  18. 24
  19. 34
  20. 23
  21. 46
  22. 67
  23. 86
  24. 17
  25. 4.6
  26. 61
  27. 6.5
  28. 9.9
  29. 74
  30. 66
  31. 9.1
  32. 46
  33. 86
  34. 24
  35. 6.3
  36. 54
  37. 7.8
  38. 70
  39. 5.2
  40. 5.4

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