← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 459 · 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) 7.9 (b) 8.1 (c) 8.0 (d) 7.8
  2. 2.√94 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.9 (d) 9.7
  3. 3.Best estimate of 2022 ÷ 76? (a) 250 (b) 2500 (c) 25
  4. 4.Best estimate of 2031 ÷ 43? (a) 5100 (b) 510 (c) 51
  5. 5.√63 to 1 decimal place? (a) 7.8 (b) 7.6 (c) 7.9 (d) 7.7
  6. 6.Best estimate of 1533 ÷ 39? (a) 38 (b) 380 (c) 3800
  7. 7.√84 to 1 decimal place? (a) 9.2 (b) 9.1 (c) 9.0 (d) 9.3
  8. 8.Best estimate of 1419 ÷ 39? (a) 35 (b) 350 (c) 3500
  9. 9.Best estimate of 1795 ÷ 72? (a) 26 (b) 2600 (c) 260
  10. 10.Best estimate of 6155 ÷ 82? (a) 7700 (b) 77 (c) 770
  11. 11.Best estimate of 5443 ÷ 89? (a) 600 (b) 6000 (c) 60
  12. 12.√21 to 1 decimal place? (a) 4.6 (b) 4.9 (c) 4.7 (d) 4.8
  13. 13.√34 to 1 decimal place? (a) 5.8 (b) 5.7 (c) 5.9 (d) 5.6
  14. 14.√78 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 9.0
  15. 15.√96 to 1 decimal place? (a) 9.6 (b) 9.8 (c) 9.5 (d) 9.7
  16. 16.√79 to 1 decimal place? (a) 9.0 (b) 8.8 (c) 8.9 (d) 9.1
  17. 17.Best estimate of 431 ÷ 31? (a) 14 (b) 1400 (c) 140
  18. 18.Best estimate of 2990 ÷ 41? (a) 7500 (b) 75 (c) 750
  19. 19.Best estimate of 3528 ÷ 53? (a) 7100 (b) 71 (c) 710
  20. 20.√89 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.3 (d) 9.6
  21. 21.√88 to 1 decimal place? (a) 9.4 (b) 9.5 (c) 9.6 (d) 9.3
  22. 22.√26 to 1 decimal place? (a) 5.3 (b) 5.2 (c) 5.0 (d) 5.1
  23. 23.Best estimate of 3518 ÷ 62? (a) 5900 (b) 590 (c) 59
  24. 24.Best estimate of 1327 ÷ 57? (a) 22 (b) 2200 (c) 220
  25. 25.Best estimate of 3730 ÷ 66? (a) 5300 (b) 53 (c) 530
  26. 26.√74 to 1 decimal place? (a) 8.7 (b) 8.6 (c) 8.8 (d) 8.9
  27. 27.Best estimate of 2395 ÷ 73? (a) 3400 (b) 340 (c) 34
  28. 28.Best estimate of 1673 ÷ 56? (a) 28 (b) 280 (c) 2800
  29. 29.√70 to 1 decimal place? (a) 8.4 (b) 8.6 (c) 8.7 (d) 8.5
  30. 30.√75 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.9 (d) 8.6
  31. 31.Best estimate of 1237 ÷ 66? (a) 180 (b) 1800 (c) 18
  32. 32.Best estimate of 3510 ÷ 46? (a) 70 (b) 700 (c) 7000
  33. 33.Best estimate of 2890 ÷ 36? (a) 7200 (b) 720 (c) 72
  34. 34.√53 to 1 decimal place? (a) 7.4 (b) 7.3 (c) 7.1 (d) 7.2
  35. 35.√23 to 1 decimal place? (a) 5.0 (b) 4.9 (c) 4.7 (d) 4.8
  36. 36.Best estimate of 707 ÷ 43? (a) 180 (b) 1800 (c) 18
  37. 37.Best estimate of 1936 ÷ 77? (a) 2400 (b) 24 (c) 240
  38. 38.Best estimate of 4787 ÷ 76? (a) 6000 (b) 60 (c) 600
  39. 39.Best estimate of 3625 ÷ 56? (a) 600 (b) 6000 (c) 60
  40. 40.Best estimate of 1918 ÷ 29? (a) 640 (b) 6400 (c) 64

Answer key

  1. 7.8
  2. 9.7
  3. 25
  4. 51
  5. 7.9
  6. 38
  7. 9.2
  8. 35
  9. 26
  10. 77
  11. 60
  12. 4.6
  13. 5.8
  14. 8.8
  15. 9.8
  16. 8.9
  17. 14
  18. 75
  19. 71
  20. 9.4
  21. 9.4
  22. 5.1
  23. 59
  24. 22
  25. 53
  26. 8.6
  27. 34
  28. 28
  29. 8.4
  30. 8.7
  31. 18
  32. 70
  33. 72
  34. 7.3
  35. 4.8
  36. 18
  37. 24
  38. 60
  39. 60
  40. 64

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