There are three zeros in the nature and simplification of the absolute value of math problems in Grade One: -3,-1, 2. When x =-1, the original formula takes the minimum value of 3+2=5.

⑵ Four zeros: -3,-1, 2, 4. When-1≤x≤2, the original formula takes the minimum value of 7+3= 10.

(3) Two zeros: 3, 7. When x≤3, the original formula = 3- x+7-x = -2x+ 10.

When 3 < x < 7, the original formula = x-3.