3×(十五分之二+十二分之五)减三分之二
=3*(2/15)+3*(5/12)-2/3
=2/5+5/4-2/3
=24/60+75/60-40/60
=59/60
12×5×(五分之一+十二分之一)
=60*(1/5+1/12)
=60*(1/5)+60*(1/12)
=12+5
=17
3×(十五分之二+十二分之五)减三分之二
=3*(2/15)+3*(5/12)-2/3
=2/5+5/4-2/3
=24/60+75/60-40/60
=59/60
12×5×(五分之一+十二分之一)
=60*(1/5+1/12)
=60*(1/5)+60*(1/12)
=12+5
=17