← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 521 · 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.√98 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  2. 2.√32 to 1 decimal place? (a) 5.8 (b) 6.0 (c) 5.7 (d) 5.9
  3. 3.Best estimate of 1646 ÷ 64? (a) 2700 (b) 270 (c) 27
  4. 4.Best estimate of 1120 ÷ 57? (a) 1900 (b) 190 (c) 19
  5. 5.√28 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.2 (d) 5.3
  6. 6.Best estimate of 4386 ÷ 71? (a) 6300 (b) 630 (c) 63
  7. 7.Best estimate of 4580 ÷ 54? (a) 920 (b) 92 (c) 9200
  8. 8.Best estimate of 2269 ÷ 26? (a) 760 (b) 76 (c) 7600
  9. 9.Best estimate of 4049 ÷ 86? (a) 45 (b) 450 (c) 4500
  10. 10.Best estimate of 2451 ÷ 31? (a) 82 (b) 8200 (c) 820
  11. 11.Best estimate of 2845 ÷ 52? (a) 5700 (b) 570 (c) 57
  12. 12.√38 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.3 (d) 6.4
  13. 13.Best estimate of 2111 ÷ 67? (a) 3000 (b) 300 (c) 30
  14. 14.Best estimate of 2478 ÷ 77? (a) 3100 (b) 31 (c) 310
  15. 15.√92 to 1 decimal place? (a) 9.7 (b) 9.8 (c) 9.6 (d) 9.9
  16. 16.Best estimate of 2464 ÷ 51? (a) 4900 (b) 490 (c) 49
  17. 17.Best estimate of 2085 ÷ 36? (a) 52 (b) 520 (c) 5200
  18. 18.Best estimate of 3031 ÷ 56? (a) 51 (b) 510 (c) 5100
  19. 19.√46 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 7.0 (d) 6.8
  20. 20.Best estimate of 3323 ÷ 82? (a) 420 (b) 4200 (c) 42
  21. 21.Best estimate of 4124 ÷ 83? (a) 5200 (b) 520 (c) 52
  22. 22.√20 to 1 decimal place? (a) 4.5 (b) 4.7 (c) 4.8 (d) 4.6
  23. 23.Best estimate of 6526 ÷ 69? (a) 930 (b) 93 (c) 9300
  24. 24.√69 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.3 (d) 8.2
  25. 25.√87 to 1 decimal place? (a) 9.6 (b) 9.5 (c) 9.3 (d) 9.4
  26. 26.Best estimate of 1272 ÷ 67? (a) 18 (b) 180 (c) 1800
  27. 27.√59 to 1 decimal place? (a) 7.8 (b) 7.7 (c) 7.5 (d) 7.6
  28. 28.Best estimate of 1468 ÷ 88? (a) 1600 (b) 16 (c) 160
  29. 29.Best estimate of 2462 ÷ 48? (a) 4900 (b) 490 (c) 49
  30. 30.Best estimate of 4972 ÷ 67? (a) 71 (b) 7100 (c) 710
  31. 31.Best estimate of 1916 ÷ 34? (a) 640 (b) 6400 (c) 64
  32. 32.√71 to 1 decimal place? (a) 8.5 (b) 8.4 (c) 8.2 (d) 8.3
  33. 33.Best estimate of 804 ÷ 28? (a) 27 (b) 2700 (c) 270
  34. 34.Best estimate of 3136 ÷ 81? (a) 390 (b) 3900 (c) 39
  35. 35.Best estimate of 1551 ÷ 84? (a) 19 (b) 1900 (c) 190
  36. 36.Best estimate of 1447 ÷ 74? (a) 210 (b) 21 (c) 2100
  37. 37.√82 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.4
  38. 38.Best estimate of 6741 ÷ 74? (a) 9600 (b) 960 (c) 96
  39. 39.√74 to 1 decimal place? (a) 8.6 (b) 8.5 (c) 8.8 (d) 8.7
  40. 40.√31 to 1 decimal place? (a) 5.7 (b) 5.8 (c) 5.5 (d) 5.6

Answer key

  1. 9.9
  2. 5.7
  3. 27
  4. 19
  5. 5.3
  6. 63
  7. 92
  8. 76
  9. 45
  10. 82
  11. 57
  12. 6.2
  13. 30
  14. 31
  15. 9.6
  16. 49
  17. 52
  18. 51
  19. 6.8
  20. 42
  21. 52
  22. 4.5
  23. 93
  24. 8.3
  25. 9.3
  26. 18
  27. 7.7
  28. 16
  29. 49
  30. 71
  31. 64
  32. 8.4
  33. 27
  34. 39
  35. 19
  36. 21
  37. 9.1
  38. 96
  39. 8.6
  40. 5.6

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