← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 38 · 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.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 5.8 (d) 6.1
  2. 2.√40 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.3 (d) 6.5
  3. 3.Best estimate of 1127 ÷ 34? (a) 380 (b) 38 (c) 3800
  4. 4.Best estimate of 2514 ÷ 27? (a) 84 (b) 840 (c) 8400
  5. 5.√92 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.5 (d) 9.7
  6. 6.√85 to 1 decimal place? (a) 9.5 (b) 9.3 (c) 9.4 (d) 9.2
  7. 7.Best estimate of 541 ÷ 36? (a) 14 (b) 140 (c) 1400
  8. 8.√80 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.7 (d) 8.9
  9. 9.√58 to 1 decimal place? (a) 7.5 (b) 7.8 (c) 7.7 (d) 7.6
  10. 10.√22 to 1 decimal place? (a) 4.8 (b) 4.5 (c) 4.6 (d) 4.7
  11. 11.Best estimate of 2065 ÷ 53? (a) 410 (b) 41 (c) 4100
  12. 12.Best estimate of 2319 ÷ 28? (a) 7700 (b) 77 (c) 770
  13. 13.Best estimate of 1805 ÷ 34? (a) 600 (b) 60 (c) 6000
  14. 14.√79 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 9.0 (d) 8.8
  15. 15.√38 to 1 decimal place? (a) 6.4 (b) 6.3 (c) 6.5 (d) 6.2
  16. 16.Best estimate of 1728 ÷ 87? (a) 190 (b) 19 (c) 1900
  17. 17.Best estimate of 558 ÷ 36? (a) 140 (b) 1400 (c) 14
  18. 18.Best estimate of 2305 ÷ 27? (a) 7700 (b) 770 (c) 77
  19. 19.√98 to 1 decimal place? (a) 10.0 (b) 9.9 (c) 9.8 (d) 9.7
  20. 20.Best estimate of 2459 ÷ 26? (a) 82 (b) 8200 (c) 820
  21. 21.Best estimate of 6315 ÷ 76? (a) 790 (b) 79 (c) 7900
  22. 22.√74 to 1 decimal place? (a) 8.5 (b) 8.7 (c) 8.4 (d) 8.6
  23. 23.√65 to 1 decimal place? (a) 8.0 (b) 8.1 (c) 7.9 (d) 7.8
  24. 24.√55 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.2
  25. 25.√51 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.1 (d) 7.0
  26. 26.Best estimate of 2956 ÷ 86? (a) 330 (b) 3300 (c) 33
  27. 27.√70 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.3 (d) 8.4
  28. 28.√24 to 1 decimal place? (a) 5.1 (b) 4.9 (c) 5.2 (d) 5.0
  29. 29.Best estimate of 7790 ÷ 83? (a) 97 (b) 970 (c) 9700
  30. 30.Best estimate of 1398 ÷ 66? (a) 2000 (b) 20 (c) 200
  31. 31.Best estimate of 7235 ÷ 88? (a) 800 (b) 80 (c) 8000
  32. 32.Best estimate of 2281 ÷ 39? (a) 5700 (b) 570 (c) 57
  33. 33.√69 to 1 decimal place? (a) 8.3 (b) 8.4 (c) 8.6 (d) 8.5
  34. 34.Best estimate of 7398 ÷ 82? (a) 9200 (b) 92 (c) 920
  35. 35.Best estimate of 1908 ÷ 31? (a) 6400 (b) 640 (c) 64
  36. 36.Best estimate of 7544 ÷ 83? (a) 94 (b) 940 (c) 9400
  37. 37.√56 to 1 decimal place? (a) 7.7 (b) 7.4 (c) 7.6 (d) 7.5
  38. 38.Best estimate of 2891 ÷ 64? (a) 4800 (b) 480 (c) 48
  39. 39.√35 to 1 decimal place? (a) 5.8 (b) 5.6 (c) 5.9 (d) 5.7
  40. 40.Best estimate of 2451 ÷ 58? (a) 4100 (b) 41 (c) 410

Answer key

  1. 6.1
  2. 6.3
  3. 38
  4. 84
  5. 9.6
  6. 9.2
  7. 14
  8. 8.9
  9. 7.6
  10. 4.7
  11. 41
  12. 77
  13. 60
  14. 8.9
  15. 6.2
  16. 19
  17. 14
  18. 77
  19. 9.9
  20. 82
  21. 79
  22. 8.6
  23. 8.1
  24. 7.4
  25. 7.1
  26. 33
  27. 8.4
  28. 4.9
  29. 97
  30. 20
  31. 80
  32. 57
  33. 8.3
  34. 92
  35. 64
  36. 94
  37. 7.5
  38. 48
  39. 5.9
  40. 41

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