← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 698 · 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 545 ÷ 43? (a) 1400 (b) 14 (c) 140
  2. 2.Best estimate of 682 ÷ 23? (a) 340 (b) 34 (c) 3400
  3. 3.Best estimate of 1934 ÷ 83? (a) 24 (b) 240 (c) 2400
  4. 4.√78 to 1 decimal place? (a) 8.7 (b) 8.8 (c) 8.9 (d) 8.6
  5. 5.Best estimate of 2249 ÷ 59? (a) 370 (b) 37 (c) 3700
  6. 6.√28 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.3 (d) 5.4
  7. 7.√26 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 4.8 (d) 4.9
  8. 8.Best estimate of 1239 ÷ 61? (a) 210 (b) 2100 (c) 21
  9. 9.√63 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 8.2
  10. 10.√40 to 1 decimal place? (a) 6.3 (b) 6.5 (c) 6.4 (d) 6.2
  11. 11.√66 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 8.2 (d) 8.3
  12. 12.Best estimate of 1672 ÷ 32? (a) 560 (b) 5600 (c) 56
  13. 13.√80 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 9.0 (d) 8.8
  14. 14.√96 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 9.6
  15. 15.Best estimate of 718 ÷ 37? (a) 180 (b) 1800 (c) 18
  16. 16.Best estimate of 1718 ÷ 21? (a) 86 (b) 8600 (c) 860
  17. 17.Best estimate of 3636 ÷ 54? (a) 73 (b) 730 (c) 7300
  18. 18.√29 to 1 decimal place? (a) 5.1 (b) 5.4 (c) 5.3 (d) 5.2
  19. 19.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 8.0
  20. 20.Best estimate of 1567 ÷ 53? (a) 3100 (b) 310 (c) 31
  21. 21.Best estimate of 2294 ÷ 26? (a) 760 (b) 7600 (c) 76
  22. 22.Best estimate of 1657 ÷ 71? (a) 24 (b) 240 (c) 2400
  23. 23.√23 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 5.1 (d) 4.8
  24. 24.Best estimate of 5158 ÷ 84? (a) 64 (b) 640 (c) 6400
  25. 25.Best estimate of 4561 ÷ 49? (a) 910 (b) 9100 (c) 91
  26. 26.√52 to 1 decimal place? (a) 7.5 (b) 7.2 (c) 7.3 (d) 7.4
  27. 27.Best estimate of 1943 ÷ 32? (a) 6500 (b) 650 (c) 65
  28. 28.√31 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.4 (d) 5.7
  29. 29.Best estimate of 5187 ÷ 76? (a) 6500 (b) 65 (c) 650
  30. 30.√32 to 1 decimal place? (a) 5.8 (b) 5.9 (c) 5.7 (d) 5.6
  31. 31.Best estimate of 1746 ÷ 26? (a) 580 (b) 58 (c) 5800
  32. 32.√62 to 1 decimal place? (a) 8.2 (b) 7.9 (c) 8.1 (d) 8.0
  33. 33.√85 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.3 (d) 9.1
  34. 34.√58 to 1 decimal place? (a) 7.4 (b) 7.5 (c) 7.6 (d) 7.3
  35. 35.Best estimate of 494 ÷ 31? (a) 160 (b) 1600 (c) 16
  36. 36.Best estimate of 769 ÷ 32? (a) 260 (b) 2600 (c) 26
  37. 37.√90 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.5
  38. 38.Best estimate of 2259 ÷ 24? (a) 1130 (b) 11300 (c) 113
  39. 39.Best estimate of 890 ÷ 37? (a) 2200 (b) 220 (c) 22
  40. 40.√37 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.9 (d) 6.1

Answer key

  1. 14
  2. 34
  3. 24
  4. 8.8
  5. 37
  6. 5.3
  7. 5.1
  8. 21
  9. 7.9
  10. 6.3
  11. 8.1
  12. 56
  13. 8.9
  14. 9.8
  15. 18
  16. 86
  17. 73
  18. 5.4
  19. 7.8
  20. 31
  21. 76
  22. 24
  23. 4.8
  24. 64
  25. 91
  26. 7.2
  27. 65
  28. 5.6
  29. 65
  30. 5.7
  31. 58
  32. 7.9
  33. 9.2
  34. 7.6
  35. 16
  36. 26
  37. 9.5
  38. 113
  39. 22
  40. 6.1

Free mental maths lessons, practice and worksheets at talentjr.in/mental-maths