计算 1又1/4-9/20+11/30-13/42+15/56-17/72+19/9= 脱式计算哈
问题描述:
计算 1又1/4-9/20+11/30-13/42+15/56-17/72+19/9= 脱式计算哈
答
原式=5/4-(1/4+1/5)+(1/5+1/6)-(1/7+1/6)+(1/7+1/8)-(1/8+1/9)+19/9
=5/4-1/4-1/5+1/5+1/6-1/6-1/7+1/7+1/8-1/8-1/9+19/9
=1-1/9+19/9
=1+2
=3