← Estimate divisions and square roots lesson New set →

Estimating Square Roots and Division Worksheet

Mental maths lesson 27: Estimate divisions and square roots · Set 35 · 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.√21 to 1 decimal place? (a) 4.7 (b) 4.9 (c) 4.6 (d) 4.8
  2. 2.√20 to 1 decimal place? (a) 4.3 (b) 4.2 (c) 4.4 (d) 4.5
  3. 3.Best estimate of 518 ÷ 36? (a) 130 (b) 1300 (c) 13
  4. 4.Best estimate of 2331 ÷ 28? (a) 7800 (b) 78 (c) 780
  5. 5.Best estimate of 602 ÷ 32? (a) 2000 (b) 200 (c) 20
  6. 6.√84 to 1 decimal place? (a) 9.1 (b) 9.3 (c) 9.2 (d) 9.0
  7. 7.Best estimate of 1188 ÷ 49? (a) 24 (b) 240 (c) 2400
  8. 8.Best estimate of 2482 ÷ 87? (a) 280 (b) 2800 (c) 28
  9. 9.√65 to 1 decimal place? (a) 8.1 (b) 8.4 (c) 8.2 (d) 8.3
  10. 10.Best estimate of 1544 ÷ 72? (a) 2200 (b) 220 (c) 22
  11. 11.Best estimate of 556 ÷ 22? (a) 28 (b) 2800 (c) 280
  12. 12.√40 to 1 decimal place? (a) 6.2 (b) 6.1 (c) 6.3 (d) 6.4
  13. 13.Best estimate of 4480 ÷ 56? (a) 7500 (b) 75 (c) 750
  14. 14.√31 to 1 decimal place? (a) 5.5 (b) 5.4 (c) 5.3 (d) 5.6
  15. 15.Best estimate of 3950 ÷ 89? (a) 440 (b) 4400 (c) 44
  16. 16.√76 to 1 decimal place? (a) 9.0 (b) 8.9 (c) 8.7 (d) 8.8
  17. 17.Best estimate of 2098 ÷ 62? (a) 3500 (b) 350 (c) 35
  18. 18.√32 to 1 decimal place? (a) 5.6 (b) 5.4 (c) 5.5 (d) 5.7
  19. 19.√74 to 1 decimal place? (a) 8.8 (b) 8.7 (c) 8.6 (d) 8.5
  20. 20.Best estimate of 420 ÷ 27? (a) 140 (b) 14 (c) 1400
  21. 21.Best estimate of 3818 ÷ 42? (a) 950 (b) 95 (c) 9500
  22. 22.√35 to 1 decimal place? (a) 6.2 (b) 5.9 (c) 6.0 (d) 6.1
  23. 23.√42 to 1 decimal place? (a) 6.6 (b) 6.5 (c) 6.7 (d) 6.4
  24. 24.√89 to 1 decimal place? (a) 9.3 (b) 9.4 (c) 9.2 (d) 9.5
  25. 25.Best estimate of 1183 ÷ 52? (a) 2400 (b) 24 (c) 240
  26. 26.√50 to 1 decimal place? (a) 7.2 (b) 7.0 (c) 6.9 (d) 7.1
  27. 27.√61 to 1 decimal place? (a) 8.0 (b) 7.9 (c) 7.7 (d) 7.8
  28. 28.Best estimate of 2846 ÷ 63? (a) 47 (b) 470 (c) 4700
  29. 29.Best estimate of 502 ÷ 23? (a) 250 (b) 2500 (c) 25
  30. 30.Best estimate of 7029 ÷ 76? (a) 8800 (b) 880 (c) 88
  31. 31.√55 to 1 decimal place? (a) 7.4 (b) 7.6 (c) 7.3 (d) 7.5
  32. 32.√78 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  33. 33.√46 to 1 decimal place? (a) 6.9 (b) 7.1 (c) 7.0 (d) 6.8
  34. 34.Best estimate of 1403 ÷ 36? (a) 3500 (b) 350 (c) 35
  35. 35.Best estimate of 1083 ÷ 48? (a) 2200 (b) 220 (c) 22
  36. 36.√77 to 1 decimal place? (a) 8.6 (b) 8.8 (c) 8.5 (d) 8.7
  37. 37.√48 to 1 decimal place? (a) 7.1 (b) 6.9 (c) 6.8 (d) 7.0
  38. 38.Best estimate of 6622 ÷ 72? (a) 95 (b) 9500 (c) 950
  39. 39.Best estimate of 3060 ÷ 43? (a) 770 (b) 7700 (c) 77
  40. 40.√92 to 1 decimal place? (a) 9.6 (b) 9.7 (c) 9.4 (d) 9.5

Answer key

  1. 4.6
  2. 4.5
  3. 13
  4. 78
  5. 20
  6. 9.2
  7. 24
  8. 28
  9. 8.1
  10. 22
  11. 28
  12. 6.3
  13. 75
  14. 5.6
  15. 44
  16. 8.7
  17. 35
  18. 5.7
  19. 8.6
  20. 14
  21. 95
  22. 5.9
  23. 6.5
  24. 9.4
  25. 24
  26. 7.1
  27. 7.8
  28. 47
  29. 25
  30. 88
  31. 7.4
  32. 8.8
  33. 6.8
  34. 35
  35. 22
  36. 8.8
  37. 6.9
  38. 95
  39. 77
  40. 9.6

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