1. 7,8-2,625=7²/₅-2⁵/₈=37/5-21/8=(37*8-21*5)/(5*8)=(312-105)/40=207/40.
2. (207/40)*(16/23)=207*16/(40*23)=18/5=3,6.
3. 2⁵/₉+1¹¹/₄₅=23/9+56/45=(23*5+56)/45=(115+56)/45=171/45.
4. (171/45)*2⁷/₁₉=(171/45)*(45/19)=171*45/(45*19)=171/19=9.
5. 3,6:9=0,4.
6. 5,6+(2/5)=5,6+0,4=6.
7. 13,8:6=2,3.
8. 3-2,3=0,7.
9. 8*0,7=5,6.
10. 0,4+5,6=6.
Ответ: 6.