Question

Tính:

M= 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + 9 + 10 -...- 995 - 996 + 997 + 998

Answer 1

= 1 + (2 - 3 - 4 + 5) + (6 - 7 - 8 +9) + ..... + (994 - 995 - 996 + 997) + 998

= 1 + 0 + 0 + 0 + ....... + 0 +  998

= 1 + 998 = 999