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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 631 · 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.√44 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.6 (d) 6.5
  2. 2.Best estimate of 2422 ÷ 79? (a) 3000 (b) 300 (c) 30
  3. 3.Best estimate of 4827 ÷ 59? (a) 8000 (b) 80 (c) 800
  4. 4.√26 to 1 decimal place? (a) 4.9 (b) 5.0 (c) 4.8 (d) 5.1
  5. 5.√88 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.4 (d) 9.1
  6. 6.Best estimate of 1701 ÷ 53? (a) 340 (b) 34 (c) 3400
  7. 7.Best estimate of 8338 ÷ 89? (a) 9300 (b) 93 (c) 930
  8. 8.√29 to 1 decimal place? (a) 5.2 (b) 5.4 (c) 5.1 (d) 5.3
  9. 9.√38 to 1 decimal place? (a) 6.4 (b) 6.1 (c) 6.2 (d) 6.3
  10. 10.Best estimate of 1870 ÷ 52? (a) 3700 (b) 370 (c) 37
  11. 11.Best estimate of 1536 ÷ 59? (a) 2600 (b) 26 (c) 260
  12. 12.Best estimate of 456 ÷ 26? (a) 150 (b) 15 (c) 1500
  13. 13.Best estimate of 4835 ÷ 67? (a) 690 (b) 6900 (c) 69
  14. 14.Best estimate of 3697 ÷ 41? (a) 9200 (b) 92 (c) 920
  15. 15.Best estimate of 5966 ÷ 88? (a) 66 (b) 6600 (c) 660
  16. 16.√96 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.9 (d) 10.0
  17. 17.√84 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.3 (d) 9.0
  18. 18.Best estimate of 1453 ÷ 53? (a) 2900 (b) 290 (c) 29
  19. 19.√32 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.8 (d) 5.7
  20. 20.Best estimate of 5225 ÷ 71? (a) 7500 (b) 750 (c) 75
  21. 21.Best estimate of 2077 ÷ 32? (a) 6900 (b) 69 (c) 690
  22. 22.Best estimate of 941 ÷ 36? (a) 24 (b) 2400 (c) 240
  23. 23.Best estimate of 692 ÷ 43? (a) 17 (b) 170 (c) 1700
  24. 24.√74 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.7 (d) 8.6
  25. 25.Best estimate of 2045 ÷ 36? (a) 51 (b) 510 (c) 5100
  26. 26.Best estimate of 1866 ÷ 52? (a) 3700 (b) 37 (c) 370
  27. 27.Best estimate of 2261 ÷ 32? (a) 7500 (b) 75 (c) 750
  28. 28.Best estimate of 390 ÷ 26? (a) 13 (b) 130 (c) 1300
  29. 29.Best estimate of 685 ÷ 26? (a) 2300 (b) 230 (c) 23
  30. 30.√23 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.0 (d) 4.8
  31. 31.Best estimate of 798 ÷ 26? (a) 270 (b) 27 (c) 2700
  32. 32.Best estimate of 4723 ÷ 76? (a) 59 (b) 5900 (c) 590
  33. 33.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.4 (d) 9.2
  34. 34.Best estimate of 5914 ÷ 73? (a) 840 (b) 84 (c) 8400
  35. 35.Best estimate of 3323 ÷ 38? (a) 830 (b) 8300 (c) 83
  36. 36.√46 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 6.8 (d) 7.0
  37. 37.Best estimate of 1068 ÷ 72? (a) 150 (b) 15 (c) 1500
  38. 38.√51 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.4 (d) 7.1
  39. 39.Best estimate of 2661 ÷ 72? (a) 3800 (b) 38 (c) 380
  40. 40.Best estimate of 1352 ÷ 71? (a) 190 (b) 1900 (c) 19

Answer key

  1. 6.6
  2. 30
  3. 80
  4. 5.1
  5. 9.4
  6. 34
  7. 93
  8. 5.4
  9. 6.2
  10. 37
  11. 26
  12. 15
  13. 69
  14. 92
  15. 66
  16. 9.8
  17. 9.2
  18. 29
  19. 5.7
  20. 75
  21. 69
  22. 24
  23. 17
  24. 8.6
  25. 51
  26. 37
  27. 75
  28. 13
  29. 23
  30. 4.8
  31. 27
  32. 59
  33. 9.1
  34. 84
  35. 83
  36. 6.8
  37. 15
  38. 7.1
  39. 38
  40. 19

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