[urgent] simplify x-3-4-x, where x is less than 3

[urgent] simplify x-3-4-x, where x is less than 3

X-3-4-x
= 3-x-（4-x）
=3-x-4+x
= -1

When 1 < x < 3, simplify x-3 + X-1 / 2

1＜x＜3
x-3＜0
x-1＞0
(x-3 + x-1) / 2
=（3 - x + x -1）/2
= 1

When 1 ≤ a < 3, A-1 - A-3 =?

=a-1+a-3
=2a-4

Given the position of numbers a, B and C on the number axis as shown in the figure, the result of simplifying a + B + A + B - B-C is
Number axis: -- A-0 -- B-C - →
There is another problem. The positions of known numbers a, B and C on the number axis are shown in the figure, which is simplified as: a + C + C-B - B + a
Number axis: - a-b-0-c - →
Write out your ideas

1. It can be seen from the figure that ab > 0 and IBI > IAI,
So IAI = -- A, IBI = B,
a+b>0,b--c

Reduction of π - 4 + 3 - π

π = 3.14, smaller than 4, and π - 4 is negative
So the absolute value π - 4 = 4 - π
In addition, it is larger than 3, and 3 - π is also negative
So the absolute value is 3 - π = π - 3
π - 4 + 3 - π
=4-π+π-3
=1