Mă ajutați vă rog???

2-1/4= 8/4
7/9:8/4=7/9x4/8=28/72=7/18
1 intreg si 1/9=10/9
o.6x10/9=0.6x9:10=0.54
0.54-7/18=0.54-0.38=0.16