← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 622 · 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.√67 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.2 (d) 8.5
  2. 2.Best estimate of 904 ÷ 41? (a) 23 (b) 2300 (c) 230
  3. 3.Best estimate of 1344 ÷ 84? (a) 1700 (b) 17 (c) 170
  4. 4.√94 to 1 decimal place? (a) 9.8 (b) 9.6 (c) 9.7 (d) 9.9
  5. 5.√74 to 1 decimal place? (a) 8.3 (b) 8.6 (c) 8.4 (d) 8.5
  6. 6.√40 to 1 decimal place? (a) 6.3 (b) 6.0 (c) 6.1 (d) 6.2
  7. 7.√87 to 1 decimal place? (a) 9.6 (b) 9.3 (c) 9.4 (d) 9.5
  8. 8.Best estimate of 3214 ÷ 46? (a) 6400 (b) 640 (c) 64
  9. 9.Best estimate of 5465 ÷ 89? (a) 61 (b) 610 (c) 6100
  10. 10.Best estimate of 1320 ÷ 29? (a) 4400 (b) 440 (c) 44
  11. 11.Best estimate of 3819 ÷ 66? (a) 550 (b) 55 (c) 5500
  12. 12.√70 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.6
  13. 13.√82 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.1 (d) 9.3
  14. 14.√83 to 1 decimal place? (a) 9.1 (b) 8.9 (c) 9.0 (d) 8.8
  15. 15.√27 to 1 decimal place? (a) 5.0 (b) 5.2 (c) 4.9 (d) 5.1
  16. 16.Best estimate of 2547 ÷ 46? (a) 510 (b) 5100 (c) 51
  17. 17.√76 to 1 decimal place? (a) 8.7 (b) 8.5 (c) 8.4 (d) 8.6
  18. 18.Best estimate of 3944 ÷ 81? (a) 4900 (b) 490 (c) 49
  19. 19.Best estimate of 2612 ÷ 32? (a) 87 (b) 870 (c) 8700
  20. 20.√63 to 1 decimal place? (a) 7.6 (b) 7.9 (c) 7.7 (d) 7.8
  21. 21.Best estimate of 4492 ÷ 82? (a) 560 (b) 56 (c) 5600
  22. 22.Best estimate of 4494 ÷ 83? (a) 560 (b) 56 (c) 5600
  23. 23.Best estimate of 1022 ÷ 77? (a) 1300 (b) 13 (c) 130
  24. 24.Best estimate of 951 ÷ 29? (a) 32 (b) 3200 (c) 320
  25. 25.Best estimate of 1581 ÷ 44? (a) 40 (b) 400 (c) 4000
  26. 26.Best estimate of 1186 ÷ 43? (a) 30 (b) 300 (c) 3000
  27. 27.√88 to 1 decimal place? (a) 9.4 (b) 9.7 (c) 9.6 (d) 9.5
  28. 28.Best estimate of 7284 ÷ 81? (a) 9100 (b) 910 (c) 91
  29. 29.Best estimate of 1646 ÷ 51? (a) 33 (b) 330 (c) 3300
  30. 30.Best estimate of 1476 ÷ 46? (a) 300 (b) 30 (c) 3000
  31. 31.√45 to 1 decimal place? (a) 6.6 (b) 6.8 (c) 6.9 (d) 6.7
  32. 32.Best estimate of 4145 ÷ 57? (a) 6900 (b) 69 (c) 690
  33. 33.Best estimate of 1594 ÷ 71? (a) 230 (b) 2300 (c) 23
  34. 34.Best estimate of 611 ÷ 48? (a) 1200 (b) 120 (c) 12
  35. 35.Best estimate of 632 ÷ 21? (a) 320 (b) 3200 (c) 32
  36. 36.Best estimate of 1732 ÷ 68? (a) 25 (b) 2500 (c) 250
  37. 37.√30 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.5 (d) 5.4
  38. 38.Best estimate of 6089 ÷ 67? (a) 870 (b) 8700 (c) 87
  39. 39.Best estimate of 5669 ÷ 84? (a) 710 (b) 7100 (c) 71
  40. 40.√92 to 1 decimal place? (a) 9.4 (b) 9.7 (c) 9.5 (d) 9.6

Answer key

  1. 8.2
  2. 23
  3. 17
  4. 9.7
  5. 8.6
  6. 6.3
  7. 9.3
  8. 64
  9. 61
  10. 44
  11. 55
  12. 8.4
  13. 9.1
  14. 9.1
  15. 5.2
  16. 51
  17. 8.7
  18. 49
  19. 87
  20. 7.9
  21. 56
  22. 56
  23. 13
  24. 32
  25. 40
  26. 30
  27. 9.4
  28. 91
  29. 33
  30. 30
  31. 6.7
  32. 69
  33. 23
  34. 12
  35. 32
  36. 25
  37. 5.5
  38. 87
  39. 71
  40. 9.6

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