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Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 201 · 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 1727 ÷ 29? (a) 580 (b) 58 (c) 5800
  2. 2.Best estimate of 958 ÷ 53? (a) 1900 (b) 19 (c) 190
  3. 3.√29 to 1 decimal place? (a) 5.4 (b) 5.3 (c) 5.5 (d) 5.2
  4. 4.Best estimate of 5837 ÷ 84? (a) 730 (b) 73 (c) 7300
  5. 5.√46 to 1 decimal place? (a) 6.8 (b) 7.1 (c) 7.0 (d) 6.9
  6. 6.Best estimate of 7137 ÷ 76? (a) 890 (b) 89 (c) 8900
  7. 7.Best estimate of 3981 ÷ 84? (a) 500 (b) 50 (c) 5000
  8. 8.√69 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.6 (d) 8.3
  9. 9.Best estimate of 2002 ÷ 71? (a) 29 (b) 2900 (c) 290
  10. 10.Best estimate of 2372 ÷ 46? (a) 4700 (b) 470 (c) 47
  11. 11.Best estimate of 1443 ÷ 23? (a) 7200 (b) 72 (c) 720
  12. 12.√40 to 1 decimal place? (a) 6.4 (b) 6.1 (c) 6.2 (d) 6.3
  13. 13.√80 to 1 decimal place? (a) 8.9 (b) 8.7 (c) 8.6 (d) 8.8
  14. 14.Best estimate of 464 ÷ 23? (a) 230 (b) 2300 (c) 23
  15. 15.Best estimate of 3330 ÷ 48? (a) 67 (b) 6700 (c) 670
  16. 16.√58 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.8 (d) 7.9
  17. 17.Best estimate of 3139 ÷ 56? (a) 520 (b) 52 (c) 5200
  18. 18.√98 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 9.8 (d) 10.1
  19. 19.√26 to 1 decimal place? (a) 5.3 (b) 5.0 (c) 5.2 (d) 5.1
  20. 20.Best estimate of 1422 ÷ 38? (a) 36 (b) 360 (c) 3600
  21. 21.Best estimate of 330 ÷ 26? (a) 11 (b) 110 (c) 1100
  22. 22.Best estimate of 5378 ÷ 62? (a) 900 (b) 9000 (c) 90
  23. 23.√70 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  24. 24.Best estimate of 3009 ÷ 79? (a) 3800 (b) 38 (c) 380
  25. 25.Best estimate of 1563 ÷ 27? (a) 5200 (b) 520 (c) 52
  26. 26.√61 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.9 (d) 7.7
  27. 27.Best estimate of 1519 ÷ 88? (a) 1700 (b) 17 (c) 170
  28. 28.Best estimate of 992 ÷ 62? (a) 1700 (b) 170 (c) 17
  29. 29.√94 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.8 (d) 9.9
  30. 30.Best estimate of 863 ÷ 31? (a) 2900 (b) 290 (c) 29
  31. 31.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  32. 32.Best estimate of 1209 ÷ 56? (a) 200 (b) 20 (c) 2000
  33. 33.Best estimate of 952 ÷ 31? (a) 3200 (b) 320 (c) 32
  34. 34.√32 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.6 (d) 5.5
  35. 35.Best estimate of 3189 ÷ 36? (a) 8000 (b) 800 (c) 80
  36. 36.√42 to 1 decimal place? (a) 6.3 (b) 6.4 (c) 6.5 (d) 6.2
  37. 37.Best estimate of 527 ÷ 42? (a) 130 (b) 1300 (c) 13
  38. 38.√72 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.3 (d) 8.5
  39. 39.√37 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.3 (d) 6.1
  40. 40.Best estimate of 2166 ÷ 63? (a) 360 (b) 36 (c) 3600

Answer key

  1. 58
  2. 19
  3. 5.4
  4. 73
  5. 6.8
  6. 89
  7. 50
  8. 8.3
  9. 29
  10. 47
  11. 72
  12. 6.3
  13. 8.9
  14. 23
  15. 67
  16. 7.6
  17. 52
  18. 9.9
  19. 5.1
  20. 36
  21. 11
  22. 90
  23. 8.4
  24. 38
  25. 52
  26. 7.8
  27. 17
  28. 17
  29. 9.7
  30. 29
  31. 8.7
  32. 20
  33. 32
  34. 5.7
  35. 80
  36. 6.5
  37. 13
  38. 8.5
  39. 6.1
  40. 36

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