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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 291 · 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.√34 to 1 decimal place? (a) 6.1 (b) 5.8 (c) 5.9 (d) 6.0
  2. 2.Best estimate of 1738 ÷ 63? (a) 2900 (b) 29 (c) 290
  3. 3.Best estimate of 4329 ÷ 62? (a) 7200 (b) 720 (c) 72
  4. 4.Best estimate of 1263 ÷ 43? (a) 3200 (b) 320 (c) 32
  5. 5.√92 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.5 (d) 9.7
  6. 6.√21 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.4 (d) 4.5
  7. 7.√32 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.7 (d) 5.4
  8. 8.√55 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.2
  9. 9.√50 to 1 decimal place? (a) 7.2 (b) 7.4 (c) 7.1 (d) 7.3
  10. 10.√24 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.9 (d) 4.8
  11. 11.Best estimate of 1275 ÷ 26? (a) 430 (b) 43 (c) 4300
  12. 12.Best estimate of 1003 ÷ 66? (a) 14 (b) 140 (c) 1400
  13. 13.Best estimate of 2901 ÷ 46? (a) 580 (b) 58 (c) 5800
  14. 14.√77 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.8 (d) 8.7
  15. 15.Best estimate of 1614 ÷ 71? (a) 23 (b) 230 (c) 2300
  16. 16.Best estimate of 3163 ÷ 59? (a) 53 (b) 5300 (c) 530
  17. 17.Best estimate of 6551 ÷ 74? (a) 940 (b) 94 (c) 9400
  18. 18.Best estimate of 707 ÷ 36? (a) 18 (b) 180 (c) 1800
  19. 19.Best estimate of 5606 ÷ 88? (a) 620 (b) 6200 (c) 62
  20. 20.√70 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.2 (d) 8.5
  21. 21.√87 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 9.4 (d) 9.3
  22. 22.Best estimate of 2309 ÷ 83? (a) 2900 (b) 29 (c) 290
  23. 23.Best estimate of 1572 ÷ 88? (a) 1700 (b) 170 (c) 17
  24. 24.√65 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.3 (d) 8.2
  25. 25.Best estimate of 1460 ÷ 36? (a) 3700 (b) 370 (c) 37
  26. 26.Best estimate of 2434 ÷ 66? (a) 350 (b) 35 (c) 3500
  27. 27.Best estimate of 6694 ÷ 74? (a) 9600 (b) 960 (c) 96
  28. 28.Best estimate of 3750 ÷ 58? (a) 6300 (b) 630 (c) 63
  29. 29.√28 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.5 (d) 5.6
  30. 30.Best estimate of 2917 ÷ 56? (a) 490 (b) 4900 (c) 49
  31. 31.√98 to 1 decimal place? (a) 10.1 (b) 9.8 (c) 9.9 (d) 10.0
  32. 32.√71 to 1 decimal place? (a) 8.5 (b) 8.3 (c) 8.4 (d) 8.2
  33. 33.√62 to 1 decimal place? (a) 7.8 (b) 8.1 (c) 7.9 (d) 8.0
  34. 34.√41 to 1 decimal place? (a) 6.7 (b) 6.4 (c) 6.6 (d) 6.5
  35. 35.√79 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.2 (d) 9.1
  36. 36.Best estimate of 2988 ÷ 68? (a) 430 (b) 4300 (c) 43
  37. 37.Best estimate of 744 ÷ 42? (a) 19 (b) 1900 (c) 190
  38. 38.√59 to 1 decimal place? (a) 7.5 (b) 7.7 (c) 7.6 (d) 7.8
  39. 39.√58 to 1 decimal place? (a) 7.7 (b) 7.6 (c) 7.8 (d) 7.5
  40. 40.Best estimate of 1181 ÷ 33? (a) 39 (b) 3900 (c) 390

Answer key

  1. 5.8
  2. 29
  3. 72
  4. 32
  5. 9.6
  6. 4.6
  7. 5.7
  8. 7.4
  9. 7.1
  10. 4.9
  11. 43
  12. 14
  13. 58
  14. 8.8
  15. 23
  16. 53
  17. 94
  18. 18
  19. 62
  20. 8.4
  21. 9.3
  22. 29
  23. 17
  24. 8.1
  25. 37
  26. 35
  27. 96
  28. 63
  29. 5.3
  30. 49
  31. 9.9
  32. 8.4
  33. 7.9
  34. 6.4
  35. 8.9
  36. 43
  37. 19
  38. 7.7
  39. 7.6
  40. 39

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