← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 949 · 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 500 ÷ 21? (a) 2500 (b) 250 (c) 25
  2. 2.Best estimate of 2426 ÷ 56? (a) 400 (b) 4000 (c) 40
  3. 3.Best estimate of 3569 ÷ 47? (a) 71 (b) 710 (c) 7100
  4. 4.√67 to 1 decimal place? (a) 8.1 (b) 8.3 (c) 8.2 (d) 8.0
  5. 5.√58 to 1 decimal place? (a) 7.7 (b) 7.8 (c) 7.9 (d) 7.6
  6. 6.Best estimate of 1496 ÷ 48? (a) 30 (b) 3000 (c) 300
  7. 7.Best estimate of 5719 ÷ 84? (a) 71 (b) 710 (c) 7100
  8. 8.√41 to 1 decimal place? (a) 6.1 (b) 6.2 (c) 6.4 (d) 6.3
  9. 9.√40 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.3 (d) 6.4
  10. 10.Best estimate of 2149 ÷ 37? (a) 5400 (b) 54 (c) 540
  11. 11.Best estimate of 2019 ÷ 82? (a) 250 (b) 25 (c) 2500
  12. 12.Best estimate of 1223 ÷ 64? (a) 2000 (b) 20 (c) 200
  13. 13.Best estimate of 933 ÷ 68? (a) 13 (b) 1300 (c) 130
  14. 14.Best estimate of 1038 ÷ 64? (a) 1700 (b) 170 (c) 17
  15. 15.√72 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.5 (d) 8.7
  16. 16.Best estimate of 2927 ÷ 76? (a) 37 (b) 3700 (c) 370
  17. 17.Best estimate of 6568 ÷ 69? (a) 940 (b) 94 (c) 9400
  18. 18.Best estimate of 870 ÷ 37? (a) 22 (b) 2200 (c) 220
  19. 19.√87 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.5 (d) 9.2
  20. 20.Best estimate of 1116 ÷ 42? (a) 280 (b) 2800 (c) 28
  21. 21.Best estimate of 4195 ÷ 68? (a) 600 (b) 60 (c) 6000
  22. 22.√34 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 6.1
  23. 23.√79 to 1 decimal place? (a) 9.1 (b) 8.8 (c) 9.0 (d) 8.9
  24. 24.Best estimate of 4080 ÷ 83? (a) 51 (b) 5100 (c) 510
  25. 25.√92 to 1 decimal place? (a) 9.9 (b) 9.8 (c) 9.7 (d) 9.6
  26. 26.Best estimate of 2944 ÷ 77? (a) 370 (b) 3700 (c) 37
  27. 27.√85 to 1 decimal place? (a) 9.2 (b) 9.3 (c) 9.1 (d) 9.0
  28. 28.Best estimate of 4384 ÷ 84? (a) 55 (b) 5500 (c) 550
  29. 29.√90 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.8 (d) 9.7
  30. 30.√74 to 1 decimal place? (a) 8.5 (b) 8.6 (c) 8.3 (d) 8.4
  31. 31.Best estimate of 2666 ÷ 68? (a) 380 (b) 3800 (c) 38
  32. 32.√47 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 6.7 (d) 6.8
  33. 33.Best estimate of 3253 ÷ 42? (a) 810 (b) 81 (c) 8100
  34. 34.Best estimate of 1710 ÷ 57? (a) 290 (b) 2900 (c) 29
  35. 35.Best estimate of 5426 ÷ 58? (a) 9000 (b) 90 (c) 900
  36. 36.√76 to 1 decimal place? (a) 8.7 (b) 8.9 (c) 8.6 (d) 8.8
  37. 37.√31 to 1 decimal place? (a) 5.9 (b) 5.7 (c) 5.6 (d) 5.8
  38. 38.√78 to 1 decimal place? (a) 8.9 (b) 8.8 (c) 8.7 (d) 9.0
  39. 39.Best estimate of 2542 ÷ 87? (a) 280 (b) 28 (c) 2800
  40. 40.Best estimate of 568 ÷ 42? (a) 1400 (b) 140 (c) 14

Answer key

  1. 25
  2. 40
  3. 71
  4. 8.2
  5. 7.6
  6. 30
  7. 71
  8. 6.4
  9. 6.3
  10. 54
  11. 25
  12. 20
  13. 13
  14. 17
  15. 8.5
  16. 37
  17. 94
  18. 22
  19. 9.3
  20. 28
  21. 60
  22. 5.8
  23. 8.9
  24. 51
  25. 9.6
  26. 37
  27. 9.2
  28. 55
  29. 9.5
  30. 8.6
  31. 38
  32. 6.9
  33. 81
  34. 29
  35. 90
  36. 8.7
  37. 5.6
  38. 8.8
  39. 28
  40. 14

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