1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ...+ 301 + 302
= 1 + (2 -3 - 4 + 5) + (6 - 7 - 8 + 9) + ...+(298 - 299 - 300 + 301) + 302
= 1 + ( 2+5 - 3 - 4) + (6 + 9 - 7 - 8) + ...+(298 + 301 - 299 - 300) + 302
= 1 + (7 - 7) + (15 - 15) + ...+(599 - 599) + 302
= 1+ 0 + 0 + ...+ 0 + 302 = 303
B = 1+2-3-4+5+6-7-8+9+10-11-12+..........-299-300+301+302
B = 1+(2-3-4+5)+(6-7-8+9)+.......+(298-299-300+301)+302
B = 1+0+0+....+0+302
B = 1+302
B = 303