7/10-2/5= (7-2*2)/10=3/10
1/5+5/6=(1*6+5*5)/30=31/30
(3/10)*(31/30)=93/300=31/100
6½=13/2
(31/100) :(13/2)=(31/100)•(2/13)=62/1300=31/650
Поэтому
(7/10-2/5)×(1/5+5/6):6 1/2=31/650
1-((2+3)-(4+5)-(6+7)-(8+9)-10)=1-(5-9-13-17-10)=1-(-44)=1+44=45
Ответ: 45
((999+1):100*10*99)+99+3-2= 1000:100*10 *99 + 100 = 9900 +100 = 10000
Ответ : 10000