Compute 1-2+3-4+ -98+99 .

(1-2) + (3-4) + + (97-98) + 99 = -1 49 + 99 = 50.

jmc

algebra junior

Problem

Compute

1 - 2 + 3 - 4 + \dots - 98 + 99

Solution

(1 - 2) + (3 - 4) + \dots + (97 - 98) + 99 = - 1 \cdot 49 + 99 = 50

Final answer