解:3/4-3/5x1/8
=3/4-(3x1)/(5x8)
=3/4-3/40
=30/40-3/40
=27/40
分数加减法
1、同分母分数相加减,分母不变,即分数单位不变,分子相加减,能约分的要约分。
2、异分母分数相加减,先通分,即运用分数的基本性质将异分母分数转化为同分母分数,改变其分数单位而大小不变,再按同分母分数相加减法去计算,最后能约分的要约分。
解:3/4-3/5x1/8
=3/4-(3x1)/(5x8)
=3/4-3/40
=30/40-3/40
=27/40
4分之3减5分之3乘8分之1
3/4-3/5x1/8
=3/4-3/40
=30/40-3/40
=27/40
3/4-3/5 * 1/8
=3/4-3/40
=30/40-3/40
=27/40