(b+179)-89 = b + 179 - 89 = b + 90
b=56,75 56,75 + 90 = 146,75
(839+c)-239 = 839 + c - 239 = c + 600
c=37,98 37,98 + 600 = 637,98
(256-x)-156 = 256 - x - 156 = 100 - x
x=44,87 100 - 44,87 = 55,13
238-(38+a) = 238 - 38 - a = 200 - a
a=78,0 200 - 78,0 = 122