Because three numbers are not equal, not three zeros, there must be positive and negative, so that the algebraic sum can be zero. It may be one plus two minus or one minus two plus, so c.

2.27

(+2)-(-6)+(+8)-(- 1 1)=27

3.43 -650

It can be seen that the latter number is larger than the former number 1, and the first number is -56, so 0 is the 57th, 1 is the 58th and the hundredth is 43. Integer sum is1+2+3+...+43-(1+2+...+56) =-650.

4.d

5.d

A-b=-(b-a) So this equation holds no matter what value ab takes.

6.0

(3+ 1+0+(- 1)+2+(-2)+(-3))/7=0

7.d

Should be positive or negative.

8. I don't understand what numerator and denominator are. I suggest you put parentheses.

9.d

A should be 0 or a positive number, b can be 1 or-1, and c can be 1 or 0.

10. Positive integer 20, -|- 12|, -(-5) non-negative number 0,20, 1 and 3/4, -|- 12|, -(-5)

1 1.5/6

Mn= 1, and the original formula = 1/3+ 1/2=5/6.

12.5

A+b=0, and the original formula =|0-5|=| -5|=5.

13.7/6 km

(-2-5)/(-6)=7/6

14.3 -3

Suppose the first bracket is x and the second bracket is-x.

3x-2 *(x)= 5x = 15，x=3

15. I can't figure it out