(1/8+2/9-1/4)×5 1/7÷(7/9-2/3+1/6)=9

1)1/8+2/9=9+16/72=25/72

2)25/72-1/4=25-18/72=7/72

3)2/3+1/6=4+1/6=5/6

4)7/9-5/6=15-14/18=1/18

5)7/72×5 1/7=(7зачеркиваем)/72×36/(7зачеркиваем)=1/2

6)1/2÷1/18=1/2×18/1=9