← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 881 · 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 2520 ÷ 34? (a) 84 (b) 8400 (c) 840
  2. 2.Best estimate of 1060 ÷ 22? (a) 53 (b) 5300 (c) 530
  3. 3.√45 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.7 (d) 6.6
  4. 4.Best estimate of 4178 ÷ 71? (a) 6000 (b) 600 (c) 60
  5. 5.Best estimate of 1227 ÷ 87? (a) 140 (b) 14 (c) 1400
  6. 6.√84 to 1 decimal place? (a) 8.9 (b) 9.0 (c) 9.2 (d) 9.1
  7. 7.√76 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  8. 8.Best estimate of 1648 ÷ 67? (a) 240 (b) 2400 (c) 24
  9. 9.√65 to 1 decimal place? (a) 8.0 (b) 8.3 (c) 8.2 (d) 8.1
  10. 10.Best estimate of 2596 ÷ 52? (a) 5200 (b) 52 (c) 520
  11. 11.Best estimate of 3786 ÷ 68? (a) 5400 (b) 540 (c) 54
  12. 12.√34 to 1 decimal place? (a) 6.0 (b) 5.7 (c) 5.8 (d) 5.9
  13. 13.Best estimate of 1830 ÷ 57? (a) 3100 (b) 31 (c) 310
  14. 14.√94 to 1 decimal place? (a) 9.6 (b) 9.9 (c) 9.8 (d) 9.7
  15. 15.Best estimate of 2220 ÷ 53? (a) 44 (b) 440 (c) 4400
  16. 16.Best estimate of 5363 ÷ 83? (a) 670 (b) 67 (c) 6700
  17. 17.√20 to 1 decimal place? (a) 4.3 (b) 4.5 (c) 4.6 (d) 4.4
  18. 18.Best estimate of 2747 ÷ 66? (a) 3900 (b) 390 (c) 39
  19. 19.√85 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.1 (d) 9.2
  20. 20.Best estimate of 1925 ÷ 53? (a) 390 (b) 3900 (c) 39
  21. 21.√26 to 1 decimal place? (a) 5.0 (b) 5.2 (c) 5.1 (d) 5.3
  22. 22.Best estimate of 2884 ÷ 56? (a) 48 (b) 480 (c) 4800
  23. 23.√66 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 8.1 (d) 8.3
  24. 24.Best estimate of 1961 ÷ 34? (a) 65 (b) 650 (c) 6500
  25. 25.√29 to 1 decimal place? (a) 5.1 (b) 5.4 (c) 5.2 (d) 5.3
  26. 26.Best estimate of 4978 ÷ 71? (a) 710 (b) 7100 (c) 71
  27. 27.√82 to 1 decimal place? (a) 9.3 (b) 9.2 (c) 9.4 (d) 9.1
  28. 28.√28 to 1 decimal place? (a) 5.1 (b) 5.0 (c) 5.3 (d) 5.2
  29. 29.√98 to 1 decimal place? (a) 10.2 (b) 10.1 (c) 9.9 (d) 10.0
  30. 30.Best estimate of 611 ÷ 26? (a) 20 (b) 2000 (c) 200
  31. 31.√59 to 1 decimal place? (a) 7.7 (b) 7.9 (c) 7.8 (d) 7.6
  32. 32.√58 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.9 (d) 7.7
  33. 33.√61 to 1 decimal place? (a) 7.9 (b) 7.8 (c) 7.7 (d) 7.6
  34. 34.Best estimate of 1997 ÷ 27? (a) 6700 (b) 670 (c) 67
  35. 35.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 5.8
  36. 36.Best estimate of 4092 ÷ 88? (a) 45 (b) 4500 (c) 450
  37. 37.Best estimate of 688 ÷ 23? (a) 340 (b) 34 (c) 3400
  38. 38.Best estimate of 3376 ÷ 38? (a) 8400 (b) 840 (c) 84
  39. 39.√40 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.3 (d) 6.2
  40. 40.Best estimate of 2900 ÷ 36? (a) 730 (b) 73 (c) 7300

Answer key

  1. 84
  2. 53
  3. 6.7
  4. 60
  5. 14
  6. 9.2
  7. 8.7
  8. 24
  9. 8.1
  10. 52
  11. 54
  12. 5.8
  13. 31
  14. 9.7
  15. 44
  16. 67
  17. 4.5
  18. 39
  19. 9.2
  20. 39
  21. 5.1
  22. 48
  23. 8.1
  24. 65
  25. 5.4
  26. 71
  27. 9.1
  28. 5.3
  29. 9.9
  30. 20
  31. 7.7
  32. 7.6
  33. 7.8
  34. 67
  35. 6.1
  36. 45
  37. 34
  38. 84
  39. 6.3
  40. 73

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