| 1-(-3)|=4;

(2)| x-(-2)| = | x+2 |；

(3) According to the distance between two points on the number axis, it is defined as | x- 1 |+x+3 |, which represents the sum of the distances between x and -3.

According to the geometric meaning analysis, when x is between -3 and 1, |x- 1|+|x+3| has a minimum value of 4.

So the answer is: (1) 3,4; (2)|x+2|。