4/5-(2/3-2/10)=4/5-(2/3-1/5)=4/5-2/3+1/5=4/5+1/5-2/3=1-2/3=1/3
通分计算原式=24/30-(20/30-6/30)=24/30-14/30=10/30=1/3
4/5-(2/3-2/10)=4/5-2/3+1/5=1-2/3=1/3
如下图所示,非常简单
4/5-(2/3-2/10)=12/15-10/15+3/15=1/3