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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 837 · 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 2391 ÷ 72? (a) 3400 (b) 340 (c) 34
  2. 2.Best estimate of 3004 ÷ 34? (a) 100 (b) 1000 (c) 10000
  3. 3.Best estimate of 879 ÷ 66? (a) 13 (b) 130 (c) 1300
  4. 4.√88 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.2
  5. 5.√78 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 8.6 (d) 8.7
  6. 6.√98 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.7 (d) 9.8
  7. 7.√86 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.1
  8. 8.√96 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.9 (d) 9.7
  9. 9.Best estimate of 2584 ÷ 41? (a) 6500 (b) 650 (c) 65
  10. 10.Best estimate of 2222 ÷ 79? (a) 2800 (b) 28 (c) 280
  11. 11.Best estimate of 374 ÷ 26? (a) 1200 (b) 120 (c) 12
  12. 12.√28 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.6 (d) 5.3
  13. 13.Best estimate of 2543 ÷ 39? (a) 640 (b) 64 (c) 6400
  14. 14.√94 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.5 (d) 9.4
  15. 15.Best estimate of 1444 ÷ 52? (a) 290 (b) 29 (c) 2900
  16. 16.√31 to 1 decimal place? (a) 5.6 (b) 5.4 (c) 5.5 (d) 5.3
  17. 17.√74 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 8.7 (d) 8.6
  18. 18.√32 to 1 decimal place? (a) 5.4 (b) 5.5 (c) 5.6 (d) 5.7
  19. 19.Best estimate of 487 ÷ 27? (a) 1600 (b) 160 (c) 16
  20. 20.Best estimate of 507 ÷ 28? (a) 170 (b) 17 (c) 1700
  21. 21.Best estimate of 716 ÷ 53? (a) 14 (b) 1400 (c) 140
  22. 22.Best estimate of 1567 ÷ 66? (a) 22 (b) 2200 (c) 220
  23. 23.Best estimate of 4501 ÷ 52? (a) 9000 (b) 900 (c) 90
  24. 24.Best estimate of 3198 ÷ 57? (a) 53 (b) 5300 (c) 530
  25. 25.Best estimate of 803 ÷ 53? (a) 16 (b) 1600 (c) 160
  26. 26.Best estimate of 1408 ÷ 51? (a) 280 (b) 28 (c) 2800
  27. 27.Best estimate of 2315 ÷ 42? (a) 58 (b) 5800 (c) 580
  28. 28.√47 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 6.9 (d) 7.1
  29. 29.Best estimate of 4494 ÷ 51? (a) 9000 (b) 900 (c) 90
  30. 30.Best estimate of 2550 ÷ 62? (a) 430 (b) 43 (c) 4300
  31. 31.Best estimate of 1105 ÷ 33? (a) 37 (b) 370 (c) 3700
  32. 32.Best estimate of 2048 ÷ 51? (a) 41 (b) 410 (c) 4100
  33. 33.Best estimate of 1955 ÷ 26? (a) 650 (b) 65 (c) 6500
  34. 34.√76 to 1 decimal place? (a) 8.7 (b) 8.4 (c) 8.6 (d) 8.5
  35. 35.√92 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.6 (d) 9.8
  36. 36.√75 to 1 decimal place? (a) 8.8 (b) 8.6 (c) 8.5 (d) 8.7
  37. 37.√27 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 5.3 (d) 5.1
  38. 38.Best estimate of 1774 ÷ 31? (a) 590 (b) 5900 (c) 59
  39. 39.√65 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.1 (d) 8.3
  40. 40.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.4

Answer key

  1. 34
  2. 100
  3. 13
  4. 9.4
  5. 8.8
  6. 9.9
  7. 9.3
  8. 9.8
  9. 65
  10. 28
  11. 12
  12. 5.3
  13. 64
  14. 9.7
  15. 29
  16. 5.6
  17. 8.6
  18. 5.7
  19. 16
  20. 17
  21. 14
  22. 22
  23. 90
  24. 53
  25. 16
  26. 28
  27. 58
  28. 6.9
  29. 90
  30. 43
  31. 37
  32. 41
  33. 65
  34. 8.7
  35. 9.6
  36. 8.7
  37. 5.2
  38. 59
  39. 8.1
  40. 9.1

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