А))) -1,2+(-1,3+(-1,4))=-1,2+(-1,3-1,4)= -1,2-1,3-1,4= -(1,2+1,3+1,4)= -3,9. __________________ или так -1,2+(-1,3+(-1,4))= -1,2+(-1,3-1,4)= -1,2+(-2,7)= -1,2-2,7= -3,9. __________________________________________
Б))) (-3 3/7+ (-2 1/14))+ (-3 1/2)= (-3 3/7- 2 1/14)+ (-3 1/2)= -(3 3/7+2 1/14) + (- 3 1/2)= -( (7*3+3)/7+ (14*2+1)/14))+ (-(3*2+1)/2)= -(24/7+ 29/14)+ (-7/2)= -( (24*2)/(7*2)+ 29/14)= -(48/14+ 29/14)+ (-7/2)= -(77/14)+ (-7/2)= -(77/14+ 7/2)= -(77/14+ (7*7)/(2*7))= -(77/14+ 49/14)= - 126/14= -9 целых. _______________________________________Или так Б) (-3 3/7+ (-2 1/14))+(-3 1/2)= (-3 3/7- 2 1/14) - 3 1/2= - 3 3/7- 2 1/14 - 3 1/2= -( 3 3/7 + 2 1/14+ 3 1/2)= -( 24/7+ 29/14+ 7/2)= - ((24*2)/14+ 29/14+ (7*7)/(2*7))= -(48/14+ 29/14+ 49/14)= -126/14= -9целых.