← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 434 · 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.√37 to 1 decimal place? (a) 5.9 (b) 5.8 (c) 6.0 (d) 6.1
  2. 2.Best estimate of 1127 ÷ 27? (a) 3800 (b) 380 (c) 38
  3. 3.√71 to 1 decimal place? (a) 8.4 (b) 8.5 (c) 8.3 (d) 8.6
  4. 4.Best estimate of 1376 ÷ 78? (a) 170 (b) 1700 (c) 17
  5. 5.Best estimate of 1517 ÷ 42? (a) 380 (b) 38 (c) 3800
  6. 6.Best estimate of 1002 ÷ 47? (a) 20 (b) 200 (c) 2000
  7. 7.√28 to 1 decimal place? (a) 5.3 (b) 5.5 (c) 5.2 (d) 5.4
  8. 8.√50 to 1 decimal place? (a) 7.2 (b) 6.9 (c) 7.1 (d) 7.0
  9. 9.Best estimate of 2464 ÷ 44? (a) 62 (b) 620 (c) 6200
  10. 10.Best estimate of 5035 ÷ 56? (a) 840 (b) 8400 (c) 84
  11. 11.Best estimate of 3099 ÷ 82? (a) 39 (b) 390 (c) 3900
  12. 12.√63 to 1 decimal place? (a) 8.1 (b) 7.9 (c) 8.0 (d) 8.2
  13. 13.√98 to 1 decimal place? (a) 10.1 (b) 10.0 (c) 9.8 (d) 9.9
  14. 14.√29 to 1 decimal place? (a) 5.5 (b) 5.3 (c) 5.6 (d) 5.4
  15. 15.Best estimate of 1568 ÷ 46? (a) 3100 (b) 310 (c) 31
  16. 16.Best estimate of 1497 ÷ 24? (a) 75 (b) 7500 (c) 750
  17. 17.Best estimate of 1086 ÷ 26? (a) 360 (b) 36 (c) 3600
  18. 18.√52 to 1 decimal place? (a) 6.9 (b) 7.0 (c) 7.2 (d) 7.1
  19. 19.Best estimate of 934 ÷ 46? (a) 1900 (b) 19 (c) 190
  20. 20.Best estimate of 655 ÷ 26? (a) 220 (b) 2200 (c) 22
  21. 21.Best estimate of 1909 ÷ 52? (a) 3800 (b) 380 (c) 38
  22. 22.Best estimate of 1195 ÷ 66? (a) 1700 (b) 17 (c) 170
  23. 23.Best estimate of 1659 ÷ 89? (a) 180 (b) 1800 (c) 18
  24. 24.√84 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.0 (d) 9.3
  25. 25.√34 to 1 decimal place? (a) 5.6 (b) 5.5 (c) 5.8 (d) 5.7
  26. 26.√59 to 1 decimal place? (a) 7.5 (b) 7.6 (c) 7.7 (d) 7.4
  27. 27.Best estimate of 5017 ÷ 53? (a) 1000 (b) 100 (c) 10000
  28. 28.√72 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.5 (d) 8.8
  29. 29.Best estimate of 981 ÷ 74? (a) 140 (b) 1400 (c) 14
  30. 30.√23 to 1 decimal place? (a) 4.8 (b) 4.6 (c) 4.9 (d) 4.7
  31. 31.√53 to 1 decimal place? (a) 7.0 (b) 7.2 (c) 7.3 (d) 7.1
  32. 32.√35 to 1 decimal place? (a) 6.0 (b) 5.8 (c) 5.9 (d) 6.1
  33. 33.√24 to 1 decimal place? (a) 5.0 (b) 5.2 (c) 4.9 (d) 5.1
  34. 34.Best estimate of 1258 ÷ 22? (a) 630 (b) 6300 (c) 63
  35. 35.Best estimate of 4451 ÷ 84? (a) 560 (b) 5600 (c) 56
  36. 36.√92 to 1 decimal place? (a) 9.8 (b) 9.9 (c) 9.7 (d) 9.6
  37. 37.Best estimate of 4549 ÷ 73? (a) 65 (b) 650 (c) 6500
  38. 38.Best estimate of 2656 ÷ 32? (a) 890 (b) 8900 (c) 89
  39. 39.√20 to 1 decimal place? (a) 4.5 (b) 4.7 (c) 4.6 (d) 4.4
  40. 40.√69 to 1 decimal place? (a) 8.2 (b) 8.5 (c) 8.3 (d) 8.4

Answer key

  1. 6.1
  2. 38
  3. 8.4
  4. 17
  5. 38
  6. 20
  7. 5.3
  8. 7.1
  9. 62
  10. 84
  11. 39
  12. 7.9
  13. 9.9
  14. 5.4
  15. 31
  16. 75
  17. 36
  18. 7.2
  19. 19
  20. 22
  21. 38
  22. 17
  23. 18
  24. 9.2
  25. 5.8
  26. 7.7
  27. 100
  28. 8.5
  29. 14
  30. 4.8
  31. 7.3
  32. 5.9
  33. 4.9
  34. 63
  35. 56
  36. 9.6
  37. 65
  38. 89
  39. 4.5
  40. 8.3

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