17 − 6.5 = 효율 10.5

17.7 − 8 = 효율 9.7

22.3 − 13 = 효율 9.3

11 − 3.7 = 효율 7.3

14.7 − 9.7 = 효율 5

13 − 8 = 효율 5

13 − 8.7 = 효율 4.3

11 − 8 = 효율 3

10.7 − 8.7 = 효율 2

8 − 6 = 효율 2

4.7 − 3.4 = 효율 1.3

5.7 − 5.7 = 효율 0