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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 268 · 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.√94 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.8 (d) 9.7
  2. 2.√48 to 1 decimal place? (a) 6.6 (b) 6.9 (c) 6.7 (d) 6.8
  3. 3.Best estimate of 4155 ÷ 74? (a) 59 (b) 5900 (c) 590
  4. 4.√70 to 1 decimal place? (a) 8.5 (b) 8.7 (c) 8.6 (d) 8.4
  5. 5.√58 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.7 (d) 7.5
  6. 6.√27 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.3 (d) 5.2
  7. 7.√41 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.6 (d) 6.3
  8. 8.Best estimate of 2733 ÷ 42? (a) 68 (b) 6800 (c) 680
  9. 9.√52 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.3 (d) 7.2
  10. 10.√89 to 1 decimal place? (a) 9.4 (b) 9.7 (c) 9.6 (d) 9.5
  11. 11.√23 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.8 (d) 4.9
  12. 12.Best estimate of 2129 ÷ 63? (a) 350 (b) 3500 (c) 35
  13. 13.Best estimate of 956 ÷ 28? (a) 3200 (b) 32 (c) 320
  14. 14.√40 to 1 decimal place? (a) 6.0 (b) 6.1 (c) 6.3 (d) 6.2
  15. 15.√65 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.0 (d) 7.9
  16. 16.Best estimate of 2685 ÷ 61? (a) 45 (b) 4500 (c) 450
  17. 17.Best estimate of 3194 ÷ 47? (a) 640 (b) 6400 (c) 64
  18. 18.Best estimate of 2601 ÷ 39? (a) 650 (b) 65 (c) 6500
  19. 19.Best estimate of 2937 ÷ 63? (a) 490 (b) 4900 (c) 49
  20. 20.Best estimate of 5639 ÷ 63? (a) 94 (b) 9400 (c) 940
  21. 21.Best estimate of 4436 ÷ 52? (a) 8900 (b) 89 (c) 890
  22. 22.Best estimate of 7881 ÷ 86? (a) 880 (b) 8800 (c) 88
  23. 23.Best estimate of 1452 ÷ 34? (a) 48 (b) 4800 (c) 480
  24. 24.√35 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 5.9 (d) 6.0
  25. 25.√92 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.6 (d) 9.5
  26. 26.Best estimate of 539 ÷ 22? (a) 2700 (b) 27 (c) 270
  27. 27.Best estimate of 1915 ÷ 44? (a) 480 (b) 48 (c) 4800
  28. 28.√37 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 6.0 (d) 5.9
  29. 29.Best estimate of 2416 ÷ 59? (a) 400 (b) 4000 (c) 40
  30. 30.√96 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 10.1
  31. 31.Best estimate of 2381 ÷ 66? (a) 3400 (b) 340 (c) 34
  32. 32.Best estimate of 5063 ÷ 73? (a) 7200 (b) 720 (c) 72
  33. 33.Best estimate of 1087 ÷ 53? (a) 220 (b) 2200 (c) 22
  34. 34.Best estimate of 6022 ÷ 82? (a) 750 (b) 7500 (c) 75
  35. 35.Best estimate of 3759 ÷ 42? (a) 9400 (b) 94 (c) 940
  36. 36.Best estimate of 5703 ÷ 62? (a) 950 (b) 9500 (c) 95
  37. 37.√26 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.0
  38. 38.Best estimate of 568 ÷ 43? (a) 140 (b) 14 (c) 1400
  39. 39.Best estimate of 2998 ÷ 84? (a) 370 (b) 3700 (c) 37
  40. 40.Best estimate of 2617 ÷ 57? (a) 440 (b) 4400 (c) 44

Answer key

  1. 9.7
  2. 6.9
  3. 59
  4. 8.4
  5. 7.6
  6. 5.2
  7. 6.4
  8. 68
  9. 7.2
  10. 9.4
  11. 4.8
  12. 35
  13. 32
  14. 6.3
  15. 8.1
  16. 45
  17. 64
  18. 65
  19. 49
  20. 94
  21. 89
  22. 88
  23. 48
  24. 5.9
  25. 9.6
  26. 27
  27. 48
  28. 6.1
  29. 40
  30. 9.8
  31. 34
  32. 72
  33. 22
  34. 75
  35. 94
  36. 95
  37. 5.1
  38. 14
  39. 37
  40. 44

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