567÷567又567/568
=567÷(567×568+567)/568
=567÷(567×568+1×567)/568
=567÷[567×(568+1)/568]
=1÷569/568
=568/569为什么变成了1，我问的是这个提取了567567×568+567=567×568+1×567=567×（568+1）=567×569