← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 289 · 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.√78 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.9 (d) 9.1
  2. 2.Best estimate of 2564 ÷ 36? (a) 640 (b) 6400 (c) 64
  3. 3.Best estimate of 3133 ÷ 37? (a) 780 (b) 78 (c) 7800
  4. 4.√94 to 1 decimal place? (a) 9.5 (b) 9.7 (c) 9.4 (d) 9.6
  5. 5.√34 to 1 decimal place? (a) 5.6 (b) 5.7 (c) 5.8 (d) 5.9
  6. 6.Best estimate of 1417 ÷ 42? (a) 3500 (b) 35 (c) 350
  7. 7.√29 to 1 decimal place? (a) 5.4 (b) 5.1 (c) 5.2 (d) 5.3
  8. 8.Best estimate of 934 ÷ 38? (a) 23 (b) 230 (c) 2300
  9. 9.√82 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 9.2 (d) 9.3
  10. 10.Best estimate of 2911 ÷ 32? (a) 970 (b) 9700 (c) 97
  11. 11.√26 to 1 decimal place? (a) 5.3 (b) 5.0 (c) 5.2 (d) 5.1
  12. 12.Best estimate of 7271 ÷ 89? (a) 81 (b) 8100 (c) 810
  13. 13.Best estimate of 1397 ÷ 78? (a) 17 (b) 170 (c) 1700
  14. 14.Best estimate of 3618 ÷ 62? (a) 60 (b) 600 (c) 6000
  15. 15.√28 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 5.3 (d) 5.0
  16. 16.√46 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.6 (d) 6.9
  17. 17.√22 to 1 decimal place? (a) 4.9 (b) 4.7 (c) 5.0 (d) 4.8
  18. 18.Best estimate of 3179 ÷ 43? (a) 7900 (b) 79 (c) 790
  19. 19.Best estimate of 2864 ÷ 37? (a) 72 (b) 720 (c) 7200
  20. 20.Best estimate of 2828 ÷ 48? (a) 57 (b) 570 (c) 5700
  21. 21.Best estimate of 1126 ÷ 67? (a) 160 (b) 16 (c) 1600
  22. 22.Best estimate of 641 ÷ 26? (a) 2100 (b) 210 (c) 21
  23. 23.√43 to 1 decimal place? (a) 6.7 (b) 6.8 (c) 6.6 (d) 6.9
  24. 24.Best estimate of 772 ÷ 21? (a) 3900 (b) 39 (c) 390
  25. 25.√45 to 1 decimal place? (a) 6.7 (b) 6.6 (c) 6.8 (d) 6.9
  26. 26.Best estimate of 1471 ÷ 57? (a) 2500 (b) 250 (c) 25
  27. 27.√21 to 1 decimal place? (a) 4.4 (b) 4.7 (c) 4.6 (d) 4.5
  28. 28.Best estimate of 1761 ÷ 66? (a) 2500 (b) 25 (c) 250
  29. 29.√24 to 1 decimal place? (a) 5.1 (b) 5.2 (c) 4.9 (d) 5.0
  30. 30.Best estimate of 1724 ÷ 49? (a) 340 (b) 3400 (c) 34
  31. 31.√52 to 1 decimal place? (a) 7.2 (b) 7.3 (c) 7.4 (d) 7.1
  32. 32.Best estimate of 3787 ÷ 52? (a) 760 (b) 7600 (c) 76
  33. 33.Best estimate of 3081 ÷ 36? (a) 7700 (b) 77 (c) 770
  34. 34.√84 to 1 decimal place? (a) 9.2 (b) 8.9 (c) 9.0 (d) 9.1
  35. 35.√48 to 1 decimal place? (a) 6.7 (b) 6.9 (c) 6.8 (d) 6.6
  36. 36.Best estimate of 5594 ÷ 74? (a) 80 (b) 8000 (c) 800
  37. 37.Best estimate of 1911 ÷ 27? (a) 640 (b) 6400 (c) 64
  38. 38.√61 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.8 (d) 7.9
  39. 39.Best estimate of 7479 ÷ 84? (a) 93 (b) 930 (c) 9300
  40. 40.√41 to 1 decimal place? (a) 6.6 (b) 6.4 (c) 6.7 (d) 6.5

Answer key

  1. 8.8
  2. 64
  3. 78
  4. 9.7
  5. 5.8
  6. 35
  7. 5.4
  8. 23
  9. 9.1
  10. 97
  11. 5.1
  12. 81
  13. 17
  14. 60
  15. 5.3
  16. 6.8
  17. 4.7
  18. 79
  19. 72
  20. 57
  21. 16
  22. 21
  23. 6.6
  24. 39
  25. 6.7
  26. 25
  27. 4.6
  28. 25
  29. 4.9
  30. 34
  31. 7.2
  32. 76
  33. 77
  34. 9.2
  35. 6.9
  36. 80
  37. 64
  38. 7.8
  39. 93
  40. 6.4

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