← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 868 · 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.√21 to 1 decimal place? (a) 4.9 (b) 4.8 (c) 4.6 (d) 4.7
  2. 2.Best estimate of 759 ÷ 23? (a) 380 (b) 3800 (c) 38
  3. 3.√44 to 1 decimal place? (a) 6.6 (b) 6.7 (c) 6.5 (d) 6.8
  4. 4.√85 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.2 (d) 9.1
  5. 5.√30 to 1 decimal place? (a) 5.7 (b) 5.6 (c) 5.5 (d) 5.4
  6. 6.Best estimate of 3191 ÷ 51? (a) 640 (b) 6400 (c) 64
  7. 7.Best estimate of 2292 ÷ 26? (a) 7600 (b) 760 (c) 76
  8. 8.√55 to 1 decimal place? (a) 7.5 (b) 7.3 (c) 7.2 (d) 7.4
  9. 9.Best estimate of 1974 ÷ 26? (a) 6600 (b) 66 (c) 660
  10. 10.Best estimate of 3448 ÷ 48? (a) 69 (b) 690 (c) 6900
  11. 11.Best estimate of 3295 ÷ 41? (a) 82 (b) 820 (c) 8200
  12. 12.√38 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.2 (d) 6.3
  13. 13.√66 to 1 decimal place? (a) 8.3 (b) 8.2 (c) 8.4 (d) 8.1
  14. 14.√84 to 1 decimal place? (a) 9.1 (b) 9.2 (c) 8.9 (d) 9.0
  15. 15.Best estimate of 589 ÷ 36? (a) 150 (b) 15 (c) 1500
  16. 16.Best estimate of 2598 ÷ 31? (a) 870 (b) 87 (c) 8700
  17. 17.Best estimate of 6567 ÷ 86? (a) 730 (b) 73 (c) 7300
  18. 18.Best estimate of 5262 ÷ 81? (a) 66 (b) 6600 (c) 660
  19. 19.Best estimate of 849 ÷ 33? (a) 280 (b) 28 (c) 2800
  20. 20.Best estimate of 2264 ÷ 28? (a) 75 (b) 7500 (c) 750
  21. 21.Best estimate of 2205 ÷ 26? (a) 740 (b) 74 (c) 7400
  22. 22.Best estimate of 3361 ÷ 58? (a) 56 (b) 5600 (c) 560
  23. 23.√88 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.4 (d) 9.5
  24. 24.√26 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.0 (d) 5.3
  25. 25.Best estimate of 1500 ÷ 21? (a) 7500 (b) 750 (c) 75
  26. 26.Best estimate of 4170 ÷ 79? (a) 520 (b) 52 (c) 5200
  27. 27.Best estimate of 4271 ÷ 47? (a) 850 (b) 8500 (c) 85
  28. 28.√29 to 1 decimal place? (a) 5.4 (b) 5.1 (c) 5.2 (d) 5.3
  29. 29.Best estimate of 1305 ÷ 21? (a) 6500 (b) 650 (c) 65
  30. 30.Best estimate of 3842 ÷ 82? (a) 480 (b) 4800 (c) 48
  31. 31.√74 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.8
  32. 32.Best estimate of 1856 ÷ 79? (a) 230 (b) 23 (c) 2300
  33. 33.Best estimate of 1370 ÷ 24? (a) 6900 (b) 69 (c) 690
  34. 34.Best estimate of 2227 ÷ 86? (a) 250 (b) 2500 (c) 25
  35. 35.√51 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 7.1 (d) 6.9
  36. 36.√52 to 1 decimal place? (a) 7.4 (b) 7.2 (c) 7.5 (d) 7.3
  37. 37.√76 to 1 decimal place? (a) 8.8 (b) 8.9 (c) 8.6 (d) 8.7
  38. 38.Best estimate of 4705 ÷ 76? (a) 5900 (b) 59 (c) 590
  39. 39.Best estimate of 3575 ÷ 42? (a) 89 (b) 890 (c) 8900
  40. 40.√96 to 1 decimal place? (a) 9.9 (b) 10.0 (c) 10.1 (d) 9.8

Answer key

  1. 4.6
  2. 38
  3. 6.6
  4. 9.2
  5. 5.5
  6. 64
  7. 76
  8. 7.4
  9. 66
  10. 69
  11. 82
  12. 6.2
  13. 8.1
  14. 9.2
  15. 15
  16. 87
  17. 73
  18. 66
  19. 28
  20. 75
  21. 74
  22. 56
  23. 9.4
  24. 5.1
  25. 75
  26. 52
  27. 85
  28. 5.4
  29. 65
  30. 48
  31. 8.6
  32. 23
  33. 69
  34. 25
  35. 7.1
  36. 7.2
  37. 8.7
  38. 59
  39. 89
  40. 9.8

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