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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 253 · 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.√37 to 1 decimal place? (a) 6.2 (b) 6.3 (c) 6.1 (d) 6.4
  2. 2.Best estimate of 2317 ÷ 72? (a) 3300 (b) 33 (c) 330
  3. 3.Best estimate of 920 ÷ 69? (a) 13 (b) 1300 (c) 130
  4. 4.Best estimate of 4617 ÷ 79? (a) 5800 (b) 58 (c) 580
  5. 5.Best estimate of 1037 ÷ 39? (a) 26 (b) 260 (c) 2600
  6. 6.Best estimate of 4756 ÷ 53? (a) 950 (b) 9500 (c) 95
  7. 7.Best estimate of 1376 ÷ 52? (a) 28 (b) 280 (c) 2800
  8. 8.Best estimate of 555 ÷ 26? (a) 190 (b) 19 (c) 1900
  9. 9.√72 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.2
  10. 10.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.4 (d) 9.3
  11. 11.√45 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.8 (d) 6.7
  12. 12.Best estimate of 857 ÷ 31? (a) 29 (b) 2900 (c) 290
  13. 13.√46 to 1 decimal place? (a) 6.5 (b) 6.6 (c) 6.7 (d) 6.8
  14. 14.Best estimate of 1541 ÷ 33? (a) 51 (b) 510 (c) 5100
  15. 15.√69 to 1 decimal place? (a) 8.4 (b) 8.2 (c) 8.3 (d) 8.5
  16. 16.Best estimate of 4785 ÷ 84? (a) 6000 (b) 60 (c) 600
  17. 17.Best estimate of 4400 ÷ 88? (a) 4900 (b) 490 (c) 49
  18. 18.√22 to 1 decimal place? (a) 4.8 (b) 4.9 (c) 4.7 (d) 4.6
  19. 19.Best estimate of 3072 ÷ 67? (a) 4400 (b) 440 (c) 44
  20. 20.Best estimate of 3721 ÷ 87? (a) 41 (b) 410 (c) 4100
  21. 21.√78 to 1 decimal place? (a) 9.0 (b) 8.7 (c) 8.8 (d) 8.9
  22. 22.Best estimate of 1807 ÷ 32? (a) 6000 (b) 600 (c) 60
  23. 23.√40 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.2 (d) 6.1
  24. 24.Best estimate of 5171 ÷ 62? (a) 860 (b) 8600 (c) 86
  25. 25.Best estimate of 3345 ÷ 86? (a) 370 (b) 37 (c) 3700
  26. 26.√80 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.7 (d) 8.8
  27. 27.Best estimate of 2093 ÷ 36? (a) 520 (b) 5200 (c) 52
  28. 28.Best estimate of 3299 ÷ 87? (a) 3700 (b) 37 (c) 370
  29. 29.√86 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.5 (d) 9.4
  30. 30.Best estimate of 1358 ÷ 73? (a) 190 (b) 1900 (c) 19
  31. 31.Best estimate of 2953 ÷ 36? (a) 7400 (b) 74 (c) 740
  32. 32.Best estimate of 536 ÷ 22? (a) 270 (b) 27 (c) 2700
  33. 33.Best estimate of 1714 ÷ 88? (a) 190 (b) 1900 (c) 19
  34. 34.√96 to 1 decimal place? (a) 9.7 (b) 10.0 (c) 9.9 (d) 9.8
  35. 35.√74 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.3 (d) 8.5
  36. 36.√87 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.6 (d) 9.3
  37. 37.Best estimate of 1320 ÷ 57? (a) 22 (b) 220 (c) 2200
  38. 38.√92 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.9 (d) 9.8
  39. 39.√89 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.5 (d) 9.7
  40. 40.Best estimate of 2518 ÷ 42? (a) 630 (b) 6300 (c) 63

Answer key

  1. 6.1
  2. 33
  3. 13
  4. 58
  5. 26
  6. 95
  7. 28
  8. 19
  9. 8.5
  10. 9.1
  11. 6.7
  12. 29
  13. 6.8
  14. 51
  15. 8.3
  16. 60
  17. 49
  18. 4.7
  19. 44
  20. 41
  21. 8.8
  22. 60
  23. 6.3
  24. 86
  25. 37
  26. 8.9
  27. 52
  28. 37
  29. 9.3
  30. 19
  31. 74
  32. 27
  33. 19
  34. 9.8
  35. 8.6
  36. 9.3
  37. 22
  38. 9.6
  39. 9.4
  40. 63

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