← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 409 · 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.√62 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.9 (d) 7.6
  2. 2.Best estimate of 4737 ÷ 66? (a) 6800 (b) 68 (c) 680
  3. 3.Best estimate of 4806 ÷ 56? (a) 800 (b) 8000 (c) 80
  4. 4.Best estimate of 7921 ÷ 89? (a) 880 (b) 8800 (c) 88
  5. 5.√61 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.9 (d) 7.6
  6. 6.Best estimate of 1404 ÷ 74? (a) 2000 (b) 200 (c) 20
  7. 7.Best estimate of 3924 ÷ 48? (a) 7800 (b) 78 (c) 780
  8. 8.√56 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.5 (d) 7.2
  9. 9.√85 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.1
  10. 10.Best estimate of 5313 ÷ 79? (a) 66 (b) 660 (c) 6600
  11. 11.√35 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 5.7
  12. 12.√34 to 1 decimal place? (a) 5.8 (b) 5.6 (c) 5.7 (d) 5.9
  13. 13.Best estimate of 3514 ÷ 57? (a) 59 (b) 590 (c) 5900
  14. 14.Best estimate of 496 ÷ 26? (a) 17 (b) 1700 (c) 170
  15. 15.√83 to 1 decimal place? (a) 9.2 (b) 9.4 (c) 9.1 (d) 9.3
  16. 16.Best estimate of 1621 ÷ 76? (a) 200 (b) 20 (c) 2000
  17. 17.√71 to 1 decimal place? (a) 8.6 (b) 8.4 (c) 8.5 (d) 8.7
  18. 18.Best estimate of 3602 ÷ 42? (a) 9000 (b) 90 (c) 900
  19. 19.√29 to 1 decimal place? (a) 5.3 (b) 5.4 (c) 5.6 (d) 5.5
  20. 20.√59 to 1 decimal place? (a) 7.8 (b) 8.0 (c) 7.7 (d) 7.9
  21. 21.Best estimate of 1217 ÷ 33? (a) 410 (b) 41 (c) 4100
  22. 22.Best estimate of 2452 ÷ 76? (a) 31 (b) 3100 (c) 310
  23. 23.√28 to 1 decimal place? (a) 5.0 (b) 5.3 (c) 5.2 (d) 5.1
  24. 24.√92 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.5 (d) 9.6
  25. 25.Best estimate of 5172 ÷ 89? (a) 5700 (b) 570 (c) 57
  26. 26.Best estimate of 4229 ÷ 66? (a) 60 (b) 6000 (c) 600
  27. 27.Best estimate of 4933 ÷ 59? (a) 820 (b) 82 (c) 8200
  28. 28.Best estimate of 1902 ÷ 81? (a) 24 (b) 240 (c) 2400
  29. 29.Best estimate of 2413 ÷ 78? (a) 300 (b) 3000 (c) 30
  30. 30.Best estimate of 1551 ÷ 47? (a) 31 (b) 310 (c) 3100
  31. 31.Best estimate of 1397 ÷ 86? (a) 160 (b) 16 (c) 1600
  32. 32.Best estimate of 1632 ÷ 62? (a) 270 (b) 27 (c) 2700
  33. 33.Best estimate of 871 ÷ 53? (a) 170 (b) 1700 (c) 17
  34. 34.√40 to 1 decimal place? (a) 6.2 (b) 6.4 (c) 6.1 (d) 6.3
  35. 35.Best estimate of 3783 ÷ 84? (a) 47 (b) 4700 (c) 470
  36. 36.Best estimate of 7271 ÷ 88? (a) 8100 (b) 810 (c) 81
  37. 37.Best estimate of 5410 ÷ 76? (a) 68 (b) 6800 (c) 680
  38. 38.√26 to 1 decimal place? (a) 5.0 (b) 5.3 (c) 5.2 (d) 5.1
  39. 39.Best estimate of 4044 ÷ 43? (a) 101 (b) 1010 (c) 10100
  40. 40.√86 to 1 decimal place? (a) 9.4 (b) 9.3 (c) 9.1 (d) 9.2

Answer key

  1. 7.9
  2. 68
  3. 80
  4. 88
  5. 7.8
  6. 20
  7. 78
  8. 7.5
  9. 9.2
  10. 66
  11. 5.9
  12. 5.8
  13. 59
  14. 17
  15. 9.1
  16. 20
  17. 8.4
  18. 90
  19. 5.4
  20. 7.7
  21. 41
  22. 31
  23. 5.3
  24. 9.6
  25. 57
  26. 60
  27. 82
  28. 24
  29. 30
  30. 31
  31. 16
  32. 27
  33. 17
  34. 6.3
  35. 47
  36. 81
  37. 68
  38. 5.1
  39. 101
  40. 9.3

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