← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 275 · 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.√98 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.7 (d) 9.8
  2. 2.Best estimate of 1966 ÷ 42? (a) 49 (b) 490 (c) 4900
  3. 3.√74 to 1 decimal place? (a) 8.5 (b) 8.8 (c) 8.6 (d) 8.7
  4. 4.Best estimate of 2913 ÷ 33? (a) 970 (b) 9700 (c) 97
  5. 5.Best estimate of 1859 ÷ 42? (a) 4600 (b) 460 (c) 46
  6. 6.Best estimate of 3058 ÷ 52? (a) 6100 (b) 61 (c) 610
  7. 7.Best estimate of 1586 ÷ 38? (a) 40 (b) 400 (c) 4000
  8. 8.Best estimate of 3613 ÷ 83? (a) 45 (b) 450 (c) 4500
  9. 9.Best estimate of 1390 ÷ 32? (a) 460 (b) 46 (c) 4600
  10. 10.Best estimate of 730 ÷ 22? (a) 370 (b) 37 (c) 3700
  11. 11.Best estimate of 3902 ÷ 46? (a) 78 (b) 780 (c) 7800
  12. 12.√34 to 1 decimal place? (a) 6.0 (b) 5.9 (c) 5.7 (d) 5.8
  13. 13.√29 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.4 (d) 5.2
  14. 14.Best estimate of 8160 ÷ 88? (a) 91 (b) 910 (c) 9100
  15. 15.Best estimate of 729 ÷ 28? (a) 2400 (b) 240 (c) 24
  16. 16.√88 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.4 (d) 9.2
  17. 17.Best estimate of 896 ÷ 57? (a) 150 (b) 15 (c) 1500
  18. 18.Best estimate of 2567 ÷ 64? (a) 430 (b) 4300 (c) 43
  19. 19.Best estimate of 2913 ÷ 42? (a) 7300 (b) 730 (c) 73
  20. 20.√22 to 1 decimal place? (a) 4.7 (b) 4.6 (c) 4.5 (d) 4.8
  21. 21.√61 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 8.1 (d) 7.8
  22. 22.√32 to 1 decimal place? (a) 5.7 (b) 5.9 (c) 6.0 (d) 5.8
  23. 23.√55 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.6
  24. 24.Best estimate of 2283 ÷ 41? (a) 570 (b) 5700 (c) 57
  25. 25.Best estimate of 7445 ÷ 84? (a) 93 (b) 9300 (c) 930
  26. 26.Best estimate of 4465 ÷ 52? (a) 890 (b) 8900 (c) 89
  27. 27.Best estimate of 470 ÷ 29? (a) 1600 (b) 16 (c) 160
  28. 28.Best estimate of 1836 ÷ 21? (a) 9200 (b) 920 (c) 92
  29. 29.√20 to 1 decimal place? (a) 4.6 (b) 4.4 (c) 4.5 (d) 4.7
  30. 30.√89 to 1 decimal place? (a) 9.5 (b) 9.4 (c) 9.6 (d) 9.3
  31. 31.Best estimate of 2315 ÷ 34? (a) 77 (b) 7700 (c) 770
  32. 32.Best estimate of 2122 ÷ 28? (a) 710 (b) 71 (c) 7100
  33. 33.Best estimate of 8146 ÷ 88? (a) 9100 (b) 91 (c) 910
  34. 34.√24 to 1 decimal place? (a) 5.0 (b) 5.1 (c) 4.9 (d) 5.2
  35. 35.√80 to 1 decimal place? (a) 9.1 (b) 8.8 (c) 8.9 (d) 9.0
  36. 36.√53 to 1 decimal place? (a) 7.5 (b) 7.4 (c) 7.3 (d) 7.6
  37. 37.√85 to 1 decimal place? (a) 9.0 (b) 9.3 (c) 9.1 (d) 9.2
  38. 38.Best estimate of 3224 ÷ 71? (a) 460 (b) 4600 (c) 46
  39. 39.√59 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.6 (d) 7.5
  40. 40.Best estimate of 1892 ÷ 29? (a) 6300 (b) 630 (c) 63

Answer key

  1. 9.9
  2. 49
  3. 8.6
  4. 97
  5. 46
  6. 61
  7. 40
  8. 45
  9. 46
  10. 37
  11. 78
  12. 5.8
  13. 5.4
  14. 91
  15. 24
  16. 9.4
  17. 15
  18. 43
  19. 73
  20. 4.7
  21. 7.8
  22. 5.7
  23. 7.4
  24. 57
  25. 93
  26. 89
  27. 16
  28. 92
  29. 4.5
  30. 9.4
  31. 77
  32. 71
  33. 91
  34. 4.9
  35. 8.9
  36. 7.3
  37. 9.2
  38. 46
  39. 7.7
  40. 63

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