手痒，试着作下练习：;P
The total money Ken had:
[(18+12)/(1-3/5)+6]/(1-1/4) = 108
The money spent on the magazines:
3/5 * [108-(108*1/4+6)]+12 = 57
The fraction of his money spent on the magazine:
57/108 = 19/36
小六应该是这样做的
The 2/5 remaining =18+12=30
The remaining = 75
3/4 of total= 75+6=81
Total=108
Magazine 45+12=57
Fraction 57/108=19/36
同意.
这边的学生应该用的是这种倒退法.