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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 739 · 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.√27 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.2 (d) 5.3
  2. 2.Best estimate of 1328 ÷ 47? (a) 270 (b) 27 (c) 2700
  3. 3.√85 to 1 decimal place? (a) 9.0 (b) 9.2 (c) 8.9 (d) 9.1
  4. 4.Best estimate of 1041 ÷ 49? (a) 2100 (b) 210 (c) 21
  5. 5.√94 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 9.7
  6. 6.√32 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.5 (d) 5.4
  7. 7.√55 to 1 decimal place? (a) 7.6 (b) 7.4 (c) 7.5 (d) 7.3
  8. 8.√80 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  9. 9.Best estimate of 2096 ÷ 58? (a) 350 (b) 3500 (c) 35
  10. 10.√79 to 1 decimal place? (a) 9.2 (b) 8.9 (c) 9.0 (d) 9.1
  11. 11.Best estimate of 1335 ÷ 51? (a) 27 (b) 2700 (c) 270
  12. 12.√96 to 1 decimal place? (a) 9.8 (b) 9.7 (c) 9.5 (d) 9.6
  13. 13.Best estimate of 1642 ÷ 31? (a) 5500 (b) 55 (c) 550
  14. 14.√63 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 7.7 (d) 7.8
  15. 15.Best estimate of 1082 ÷ 36? (a) 2700 (b) 27 (c) 270
  16. 16.Best estimate of 1586 ÷ 42? (a) 4000 (b) 40 (c) 400
  17. 17.√26 to 1 decimal place? (a) 5.2 (b) 5.0 (c) 4.9 (d) 5.1
  18. 18.Best estimate of 1407 ÷ 59? (a) 230 (b) 23 (c) 2300
  19. 19.Best estimate of 2722 ÷ 43? (a) 6800 (b) 68 (c) 680
  20. 20.√65 to 1 decimal place? (a) 7.9 (b) 8.0 (c) 8.1 (d) 7.8
  21. 21.Best estimate of 2032 ÷ 28? (a) 680 (b) 6800 (c) 68
  22. 22.Best estimate of 5665 ÷ 88? (a) 630 (b) 6300 (c) 63
  23. 23.√66 to 1 decimal place? (a) 7.9 (b) 8.1 (c) 8.0 (d) 8.2
  24. 24.√41 to 1 decimal place? (a) 6.7 (b) 6.4 (c) 6.5 (d) 6.6
  25. 25.Best estimate of 424 ÷ 21? (a) 21 (b) 210 (c) 2100
  26. 26.Best estimate of 3240 ÷ 79? (a) 41 (b) 410 (c) 4100
  27. 27.√30 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.2 (d) 5.4
  28. 28.Best estimate of 1636 ÷ 28? (a) 550 (b) 5500 (c) 55
  29. 29.√20 to 1 decimal place? (a) 4.4 (b) 4.5 (c) 4.3 (d) 4.6
  30. 30.√88 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.7 (d) 9.4
  31. 31.√52 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 7.1 (d) 7.3
  32. 32.Best estimate of 1134 ÷ 44? (a) 280 (b) 2800 (c) 28
  33. 33.Best estimate of 2133 ÷ 47? (a) 430 (b) 43 (c) 4300
  34. 34.√38 to 1 decimal place? (a) 6.3 (b) 6.1 (c) 6.0 (d) 6.2
  35. 35.Best estimate of 1706 ÷ 63? (a) 2800 (b) 280 (c) 28
  36. 36.Best estimate of 2955 ÷ 87? (a) 3300 (b) 33 (c) 330
  37. 37.√78 to 1 decimal place? (a) 9.0 (b) 8.7 (c) 8.8 (d) 8.9
  38. 38.√82 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.4 (d) 9.1
  39. 39.Best estimate of 414 ÷ 23? (a) 2100 (b) 21 (c) 210
  40. 40.√71 to 1 decimal place? (a) 8.2 (b) 8.1 (c) 8.4 (d) 8.3

Answer key

  1. 5.2
  2. 27
  3. 9.2
  4. 21
  5. 9.7
  6. 5.7
  7. 7.4
  8. 8.9
  9. 35
  10. 8.9
  11. 27
  12. 9.8
  13. 55
  14. 7.9
  15. 27
  16. 40
  17. 5.1
  18. 23
  19. 68
  20. 8.1
  21. 68
  22. 63
  23. 8.1
  24. 6.4
  25. 21
  26. 41
  27. 5.5
  28. 55
  29. 4.5
  30. 9.4
  31. 7.2
  32. 28
  33. 43
  34. 6.2
  35. 28
  36. 33
  37. 8.8
  38. 9.1
  39. 21
  40. 8.4

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