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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 834 · 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 4454 ÷ 82? (a) 5600 (b) 560 (c) 56
  2. 2.√43 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.7 (d) 6.6
  3. 3.√37 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 6.1 (d) 5.8
  4. 4.√70 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.1 (d) 8.3
  5. 5.√48 to 1 decimal place? (a) 6.9 (b) 6.8 (c) 6.6 (d) 6.7
  6. 6.√31 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.4 (d) 5.7
  7. 7.√44 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.5 (d) 6.7
  8. 8.√34 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 6.0 (d) 6.1
  9. 9.Best estimate of 1392 ÷ 88? (a) 1500 (b) 15 (c) 150
  10. 10.√63 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  11. 11.Best estimate of 2111 ÷ 76? (a) 26 (b) 260 (c) 2600
  12. 12.√41 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.2 (d) 6.3
  13. 13.Best estimate of 604 ÷ 29? (a) 20 (b) 2000 (c) 200
  14. 14.Best estimate of 804 ÷ 32? (a) 2700 (b) 27 (c) 270
  15. 15.Best estimate of 1212 ÷ 26? (a) 4000 (b) 400 (c) 40
  16. 16.√61 to 1 decimal place? (a) 7.8 (b) 8.1 (c) 7.9 (d) 8.0
  17. 17.Best estimate of 1313 ÷ 64? (a) 220 (b) 22 (c) 2200
  18. 18.Best estimate of 1495 ÷ 23? (a) 75 (b) 750 (c) 7500
  19. 19.Best estimate of 5337 ÷ 69? (a) 760 (b) 76 (c) 7600
  20. 20.Best estimate of 1673 ÷ 27? (a) 560 (b) 56 (c) 5600
  21. 21.√24 to 1 decimal place? (a) 4.7 (b) 4.8 (c) 4.9 (d) 4.6
  22. 22.√22 to 1 decimal place? (a) 4.7 (b) 5.0 (c) 4.8 (d) 4.9
  23. 23.Best estimate of 1037 ÷ 72? (a) 1500 (b) 15 (c) 150
  24. 24.√85 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.4 (d) 9.2
  25. 25.√96 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.5 (d) 9.8
  26. 26.Best estimate of 1065 ÷ 56? (a) 18 (b) 1800 (c) 180
  27. 27.√32 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.9 (d) 5.8
  28. 28.Best estimate of 2640 ÷ 29? (a) 88 (b) 8800 (c) 880
  29. 29.√75 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.5 (d) 8.7
  30. 30.Best estimate of 345 ÷ 21? (a) 1700 (b) 17 (c) 170
  31. 31.√92 to 1 decimal place? (a) 9.9 (b) 9.7 (c) 9.8 (d) 9.6
  32. 32.Best estimate of 3329 ÷ 64? (a) 5500 (b) 55 (c) 550
  33. 33.√69 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 8.3 (d) 8.1
  34. 34.Best estimate of 4698 ÷ 86? (a) 52 (b) 520 (c) 5200
  35. 35.√35 to 1 decimal place? (a) 6.1 (b) 5.9 (c) 6.0 (d) 5.8
  36. 36.√28 to 1 decimal place? (a) 5.3 (b) 5.1 (c) 5.2 (d) 5.0
  37. 37.Best estimate of 2991 ÷ 59? (a) 500 (b) 5000 (c) 50
  38. 38.√40 to 1 decimal place? (a) 6.5 (b) 6.2 (c) 6.4 (d) 6.3
  39. 39.Best estimate of 3831 ÷ 53? (a) 7700 (b) 77 (c) 770
  40. 40.√45 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.6 (d) 6.9

Answer key

  1. 56
  2. 6.6
  3. 6.1
  4. 8.4
  5. 6.9
  6. 5.6
  7. 6.6
  8. 5.8
  9. 15
  10. 7.9
  11. 26
  12. 6.4
  13. 20
  14. 27
  15. 40
  16. 7.8
  17. 22
  18. 75
  19. 76
  20. 56
  21. 4.9
  22. 4.7
  23. 15
  24. 9.2
  25. 9.8
  26. 18
  27. 5.7
  28. 88
  29. 8.7
  30. 17
  31. 9.6
  32. 55
  33. 8.3
  34. 52
  35. 5.9
  36. 5.3
  37. 50
  38. 6.3
  39. 77
  40. 6.7

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