The position of rational number AB on the number axis is shown in the figure, which is simplified as follows: (1) | a | - A; (2) | a + B |; (3) | a | + | B | (4) | b-a Simplification: (1) | a | - A; (2) | a + B |; (3) | a | + | B | (4) | b-a| Number axis:_____ B________ 0____ A_________ ▶

The position of rational number AB on the number axis is shown in the figure, which is simplified as follows: (1) | a | - A; (2) | a + B |; (3) | a | + | B | (4) | b-a Simplification: (1) | a | - A; (2) | a + B |; (3) | a | + | B | (4) | b-a| Number axis:_____ B________ 0____ A_________ ▶

It can be seen from the number axis that a is a positive number and B is a negative number, so (1) the absolute value of a - a = A-A = 0
(2) A + B is less than 0, so the absolute value of a + B is - (a + b) = - a-b
(3) Absolute value of a + absolute value of B = a-b
(4) B-A is less than 0, so the absolute value of B-A is - (B-A) = - B + a = a-b