= -2.75+0.75+ 12 and 5/7-4. 125+0. 125.

= -2-4+ 12 5/7

=6 5/7

2.(-8 3/7)+(-7.5)+(-2 1 4/7)+(+3 1/2)

== -8 3/7-2 1 4/7-7.5+3.5

= -30-3.5

= -33.5

3.(-2 1/2)+(+5/6)+(-0.5)+(+ 1 1/6);

= -2.5-0.5+5/6+ 1 and 1/6

= -3+2

= - 1

4.(- 1)+2+(-3)+4+(-5)+6+...+(-99)+ 100;

= (- 1+2)+(-3+4)……+(-99+ 100)

= 1×50

=50