23×13/22=(22+1)×13/22=13+13/22=13又13/22
23×13/22=22×13/22+1×13/22=13+13/22=13又13/22
23x13/22=(22+1)x13/22=13+13/22=13又13/22
23*13/22=(22+1)*13/22=22*13/22+1*13/22=13+13/22=13又13/22