А) 1,45 - 3,8 = 2,35
б) -0.8 - 2/3 = -8/10 - 2/3 = -4/5 - 2/3 = -12/15 - 10/15 = -22/15 = -1 7/15
в) -3/8 - (-2 3/4) = -3/8 + 11/4 = -3/8 + 22/8 = 19/8 = 2 3/8
г) 1 5/6 - (-3 1/4) + (-7 5/12) = 11/6 + 13/4 - 89/12 = 22/12 + 39/12 - 89/12 =
-28/12 = -2 4/12 = -2 1/3
a - b + c
a= -4,9
b= 7,2
c= -1,3
-4,9 - 7,2 - 1,3 = -13,4