12分之7-9分之2+2分之1
问题描述:
12分之7-9分之2+2分之1
答
=21/36-8/36+18/36
=21/36+10/36
=31/36
12分之7-9分之2+2分之1
=21/36-8/36+18/36
=21/36+10/36
=31/36