← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 992 · 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.√21 to 1 decimal place? (a) 4.6 (b) 4.7 (c) 4.5 (d) 4.4
  2. 2.√76 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.4 (d) 8.5
  3. 3.Best estimate of 7122 ÷ 89? (a) 790 (b) 79 (c) 7900
  4. 4.Best estimate of 2698 ÷ 31? (a) 9000 (b) 900 (c) 90
  5. 5.Best estimate of 6309 ÷ 67? (a) 9000 (b) 900 (c) 90
  6. 6.Best estimate of 2271 ÷ 43? (a) 57 (b) 5700 (c) 570
  7. 7.Best estimate of 580 ÷ 27? (a) 19 (b) 190 (c) 1900
  8. 8.√90 to 1 decimal place? (a) 9.7 (b) 9.4 (c) 9.5 (d) 9.6
  9. 9.Best estimate of 5497 ÷ 62? (a) 92 (b) 920 (c) 9200
  10. 10.Best estimate of 3958 ÷ 42? (a) 990 (b) 99 (c) 9900
  11. 11.Best estimate of 5172 ÷ 71? (a) 7400 (b) 740 (c) 74
  12. 12.Best estimate of 5444 ÷ 88? (a) 6000 (b) 60 (c) 600
  13. 13.√40 to 1 decimal place? (a) 6.4 (b) 6.5 (c) 6.3 (d) 6.2
  14. 14.√69 to 1 decimal place? (a) 8.0 (b) 8.2 (c) 8.3 (d) 8.1
  15. 15.Best estimate of 2439 ÷ 42? (a) 610 (b) 61 (c) 6100
  16. 16.√32 to 1 decimal place? (a) 5.7 (b) 5.5 (c) 5.4 (d) 5.6
  17. 17.Best estimate of 1959 ÷ 28? (a) 6500 (b) 650 (c) 65
  18. 18.√88 to 1 decimal place? (a) 9.4 (b) 9.1 (c) 9.3 (d) 9.2
  19. 19.Best estimate of 2725 ÷ 76? (a) 3400 (b) 340 (c) 34
  20. 20.√70 to 1 decimal place? (a) 8.4 (b) 8.3 (c) 8.1 (d) 8.2
  21. 21.√85 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 9.2
  22. 22.Best estimate of 4627 ÷ 62? (a) 770 (b) 7700 (c) 77
  23. 23.√37 to 1 decimal place? (a) 5.9 (b) 6.0 (c) 6.1 (d) 6.2
  24. 24.Best estimate of 1006 ÷ 51? (a) 2000 (b) 200 (c) 20
  25. 25.Best estimate of 2128 ÷ 67? (a) 300 (b) 3000 (c) 30
  26. 26.Best estimate of 1898 ÷ 47? (a) 380 (b) 38 (c) 3800
  27. 27.Best estimate of 461 ÷ 36? (a) 1200 (b) 12 (c) 120
  28. 28.√72 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.2
  29. 29.Best estimate of 780 ÷ 26? (a) 260 (b) 2600 (c) 26
  30. 30.√84 to 1 decimal place? (a) 9.4 (b) 9.2 (c) 9.3 (d) 9.1
  31. 31.√98 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 10.2 (d) 9.9
  32. 32.√94 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.7 (d) 9.9
  33. 33.Best estimate of 2625 ÷ 28? (a) 88 (b) 8800 (c) 880
  34. 34.Best estimate of 700 ÷ 38? (a) 1800 (b) 180 (c) 18
  35. 35.√80 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.9 (d) 9.1
  36. 36.Best estimate of 3805 ÷ 69? (a) 5400 (b) 54 (c) 540
  37. 37.√65 to 1 decimal place? (a) 8.4 (b) 8.1 (c) 8.3 (d) 8.2
  38. 38.√89 to 1 decimal place? (a) 9.4 (b) 9.6 (c) 9.7 (d) 9.5
  39. 39.Best estimate of 2747 ÷ 46? (a) 5500 (b) 55 (c) 550
  40. 40.Best estimate of 3331 ÷ 86? (a) 3700 (b) 37 (c) 370

Answer key

  1. 4.6
  2. 8.7
  3. 79
  4. 90
  5. 90
  6. 57
  7. 19
  8. 9.5
  9. 92
  10. 99
  11. 74
  12. 60
  13. 6.3
  14. 8.3
  15. 61
  16. 5.7
  17. 65
  18. 9.4
  19. 34
  20. 8.4
  21. 9.2
  22. 77
  23. 6.1
  24. 20
  25. 30
  26. 38
  27. 12
  28. 8.5
  29. 26
  30. 9.2
  31. 9.9
  32. 9.7
  33. 88
  34. 18
  35. 8.9
  36. 54
  37. 8.1
  38. 9.4
  39. 55
  40. 37

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