⑴相减法：8/9-7/8=/1/72>0,∴8/9>7/8
⑵通分法：8/9=64/72,7/8=63/72
⑶分子相同法：8/9=56/63,7/8=56/64,因为56/63>56/64,z所以8/9>7/8
⑷相除法：8/9÷7/8=8/9*8/7=64/63>1,∴8/9>7/8