← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 830 · 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 6725 ÷ 88? (a) 750 (b) 75 (c) 7500
  2. 2.Best estimate of 2638 ÷ 47? (a) 53 (b) 530 (c) 5300
  3. 3.√83 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.0
  4. 4.√80 to 1 decimal place? (a) 9.0 (b) 9.1 (c) 8.9 (d) 8.8
  5. 5.Best estimate of 3806 ÷ 51? (a) 760 (b) 7600 (c) 76
  6. 6.√30 to 1 decimal place? (a) 5.6 (b) 5.3 (c) 5.4 (d) 5.5
  7. 7.√62 to 1 decimal place? (a) 8.2 (b) 8.0 (c) 7.9 (d) 8.1
  8. 8.Best estimate of 1410 ÷ 49? (a) 28 (b) 280 (c) 2800
  9. 9.Best estimate of 1664 ÷ 36? (a) 42 (b) 4200 (c) 420
  10. 10.Best estimate of 1923 ÷ 77? (a) 240 (b) 24 (c) 2400
  11. 11.Best estimate of 1625 ÷ 33? (a) 540 (b) 54 (c) 5400
  12. 12.√90 to 1 decimal place? (a) 9.8 (b) 9.5 (c) 9.6 (d) 9.7
  13. 13.Best estimate of 3552 ÷ 52? (a) 7100 (b) 710 (c) 71
  14. 14.Best estimate of 1625 ÷ 28? (a) 540 (b) 5400 (c) 54
  15. 15.√32 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.6 (d) 5.7
  16. 16.Best estimate of 6532 ÷ 76? (a) 8200 (b) 82 (c) 820
  17. 17.Best estimate of 875 ÷ 48? (a) 1800 (b) 180 (c) 18
  18. 18.√40 to 1 decimal place? (a) 6.5 (b) 6.4 (c) 6.6 (d) 6.3
  19. 19.√26 to 1 decimal place? (a) 5.2 (b) 5.3 (c) 5.1 (d) 5.0
  20. 20.√77 to 1 decimal place? (a) 8.9 (b) 8.6 (c) 8.7 (d) 8.8
  21. 21.Best estimate of 7212 ÷ 81? (a) 900 (b) 9000 (c) 90
  22. 22.Best estimate of 1007 ÷ 44? (a) 2500 (b) 250 (c) 25
  23. 23.Best estimate of 684 ÷ 42? (a) 17 (b) 1700 (c) 170
  24. 24.Best estimate of 2463 ÷ 28? (a) 8200 (b) 820 (c) 82
  25. 25.√71 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.4
  26. 26.Best estimate of 1982 ÷ 36? (a) 500 (b) 5000 (c) 50
  27. 27.Best estimate of 4758 ÷ 62? (a) 7900 (b) 790 (c) 79
  28. 28.Best estimate of 1382 ÷ 62? (a) 2300 (b) 23 (c) 230
  29. 29.Best estimate of 1291 ÷ 21? (a) 6500 (b) 65 (c) 650
  30. 30.√82 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.4 (d) 9.3
  31. 31.Best estimate of 7314 ÷ 78? (a) 9100 (b) 910 (c) 91
  32. 32.Best estimate of 1393 ÷ 28? (a) 4600 (b) 460 (c) 46
  33. 33.Best estimate of 1072 ÷ 26? (a) 360 (b) 3600 (c) 36
  34. 34.√42 to 1 decimal place? (a) 6.8 (b) 6.6 (c) 6.7 (d) 6.5
  35. 35.√22 to 1 decimal place? (a) 4.8 (b) 4.6 (c) 4.7 (d) 4.9
  36. 36.√76 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.9 (d) 8.8
  37. 37.Best estimate of 1468 ÷ 39? (a) 3700 (b) 370 (c) 37
  38. 38.Best estimate of 1279 ÷ 39? (a) 320 (b) 3200 (c) 32
  39. 39.Best estimate of 1205 ÷ 22? (a) 6000 (b) 60 (c) 600
  40. 40.Best estimate of 5256 ÷ 68? (a) 75 (b) 750 (c) 7500

Answer key

  1. 75
  2. 53
  3. 9.1
  4. 8.9
  5. 76
  6. 5.5
  7. 7.9
  8. 28
  9. 42
  10. 24
  11. 54
  12. 9.5
  13. 71
  14. 54
  15. 5.7
  16. 82
  17. 18
  18. 6.3
  19. 5.1
  20. 8.8
  21. 90
  22. 25
  23. 17
  24. 82
  25. 8.4
  26. 50
  27. 79
  28. 23
  29. 65
  30. 9.1
  31. 91
  32. 46
  33. 36
  34. 6.5
  35. 4.7
  36. 8.7
  37. 37
  38. 32
  39. 60
  40. 75

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