15. The position of a, B and C on the number axis is shown in the figure, which is simplified |a|+|b|+|c|-|a+b|+|b-1|-|c-a| ____ C_______ b_____ 0__ 1_____ a

15. The position of a, B and C on the number axis is shown in the figure, which is simplified |a|+|b|+|c|-|a+b|+|b-1|-|c-a| ____ C_______ b_____ 0__ 1_____ a

a>1>0>b>c
|a|+|b|+|c|-|a+b|+|b-1|-|c-a| = a - b - c -(a+b) + 1 - b - a + c = 1 - 3b - a
|A + B | because the distance from a to 0 is larger than that from B to 0, so | a + B | = a + B (> 0)
|B-1 | C-A | because B < 1 C < A, the values are all negative | B-1 | = 1-B | C-A | = a - C