← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 700 · 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.√61 to 1 decimal place? (a) 7.8 (b) 7.9 (c) 7.7 (d) 7.6
  2. 2.Best estimate of 1575 ÷ 42? (a) 390 (b) 3900 (c) 39
  3. 3.√29 to 1 decimal place? (a) 5.5 (b) 5.6 (c) 5.3 (d) 5.4
  4. 4.√62 to 1 decimal place? (a) 8.1 (b) 8.2 (c) 7.9 (d) 8.0
  5. 5.Best estimate of 1913 ÷ 43? (a) 4800 (b) 480 (c) 48
  6. 6.Best estimate of 1103 ÷ 66? (a) 160 (b) 16 (c) 1600
  7. 7.Best estimate of 1655 ÷ 32? (a) 5500 (b) 550 (c) 55
  8. 8.√96 to 1 decimal place? (a) 9.7 (b) 9.6 (c) 9.5 (d) 9.8
  9. 9.Best estimate of 4987 ÷ 56? (a) 830 (b) 8300 (c) 83
  10. 10.√58 to 1 decimal place? (a) 7.6 (b) 7.7 (c) 7.5 (d) 7.8
  11. 11.Best estimate of 5102 ÷ 54? (a) 1020 (b) 10200 (c) 102
  12. 12.Best estimate of 4735 ÷ 72? (a) 680 (b) 6800 (c) 68
  13. 13.Best estimate of 1251 ÷ 81? (a) 160 (b) 16 (c) 1600
  14. 14.Best estimate of 1630 ÷ 66? (a) 2300 (b) 230 (c) 23
  15. 15.Best estimate of 3627 ÷ 81? (a) 450 (b) 4500 (c) 45
  16. 16.Best estimate of 2916 ÷ 36? (a) 730 (b) 7300 (c) 73
  17. 17.Best estimate of 3051 ÷ 78? (a) 380 (b) 3800 (c) 38
  18. 18.Best estimate of 1964 ÷ 63? (a) 3300 (b) 33 (c) 330
  19. 19.Best estimate of 5558 ÷ 86? (a) 6200 (b) 62 (c) 620
  20. 20.Best estimate of 1149 ÷ 79? (a) 1400 (b) 14 (c) 140
  21. 21.Best estimate of 5495 ÷ 82? (a) 690 (b) 6900 (c) 69
  22. 22.√74 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.6
  23. 23.√28 to 1 decimal place? (a) 5.5 (b) 5.2 (c) 5.3 (d) 5.4
  24. 24.Best estimate of 4806 ÷ 58? (a) 8000 (b) 800 (c) 80
  25. 25.Best estimate of 2223 ÷ 56? (a) 37 (b) 3700 (c) 370
  26. 26.√34 to 1 decimal place? (a) 5.9 (b) 5.6 (c) 5.7 (d) 5.8
  27. 27.Best estimate of 2282 ÷ 49? (a) 460 (b) 46 (c) 4600
  28. 28.Best estimate of 1429 ÷ 52? (a) 290 (b) 29 (c) 2900
  29. 29.√37 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.3 (d) 6.4
  30. 30.√56 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.4 (d) 7.3
  31. 31.Best estimate of 3031 ÷ 58? (a) 51 (b) 510 (c) 5100
  32. 32.Best estimate of 2185 ÷ 41? (a) 5500 (b) 55 (c) 550
  33. 33.√32 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.9 (d) 5.6
  34. 34.Best estimate of 4520 ÷ 48? (a) 900 (b) 90 (c) 9000
  35. 35.Best estimate of 4911 ÷ 62? (a) 820 (b) 8200 (c) 82
  36. 36.Best estimate of 957 ÷ 74? (a) 140 (b) 1400 (c) 14
  37. 37.√50 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 6.9 (d) 7.1
  38. 38.Best estimate of 519 ÷ 26? (a) 170 (b) 1700 (c) 17
  39. 39.√26 to 1 decimal place? (a) 5.2 (b) 5.1 (c) 5.4 (d) 5.3
  40. 40.Best estimate of 1416 ÷ 83? (a) 180 (b) 1800 (c) 18

Answer key

  1. 7.8
  2. 39
  3. 5.4
  4. 7.9
  5. 48
  6. 16
  7. 55
  8. 9.8
  9. 83
  10. 7.6
  11. 102
  12. 68
  13. 16
  14. 23
  15. 45
  16. 73
  17. 38
  18. 33
  19. 62
  20. 14
  21. 69
  22. 8.6
  23. 5.3
  24. 80
  25. 37
  26. 5.8
  27. 46
  28. 29
  29. 6.1
  30. 7.5
  31. 51
  32. 55
  33. 5.7
  34. 90
  35. 82
  36. 14
  37. 7.1
  38. 17
  39. 5.1
  40. 18

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