(7 2/5+6,4):(5,2-2 9/10)*(14-2 3/10):(3/5+0,7)=54
1. (7 2/5+6,4)=37/5+64/10=37/5+32/5= 69/5
2. (5,2-2 9/10)= 52/10-29/10= - 23/10
3. 69/5:-23/10=69/5*-10/23= 6
4. (14-2 3/10)=14-23/10=(140-23)/10= 117/10
5. (3/5+0,7)=3/5+7/10=6/10+7/10= 13/10
6. 117/10:13/10=117/10*10/13= 9
7. 6*9=54