a, 100 + 98 + 96 + ....+ 2 - 97 - 95 - .....-1
= 100 + ( 98-97)+ ( 96-95) +....+ ( 2-1)
= 100 + 1+1+...+1
= 100 +( 1.49 )
= 100 +49
= 149
b, 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 - 11 - 12 + ..... - 299 - 330 + 301 + 302
= ( 1+2 -3) + ( -4+5+6-7) + ( -8+9+10-11) +....+(- 299 - 330 + 301) + 302
= 0+ 302 = 302
c, (98. 7676 - 9898. 76 ) . (2001.2002.2003. ... 2017)
= (98.101.76-98.101.76 ) . (2001.2002.2003. ... 2017)
= 0. (2001.2002.2003. ... 2017)
= 0