Question

The value of-1+2-3+4-5+6________-2017+2018 is equals to
please answer this question step by step ​​

Answer 1

Answer:

2018 (sorry im not 100% sure)

Step-by-step explanation:

so if u pair them up -1+2 it equals 1

and that happens throughout the sequence

so 1 x 2018 = 2018

Answer 2

$\sf - 1 + 2 - 3 + 4 - ... - 2017 + 2018$

$\sf(2 + 4 + ... + 2018) - (1 + 3 + ... + 2017)$

$\sf2(1 + 2+ ... + 1009) - (1 + 3 + .. + 2017)$

$2 \times \frac{1009(1010)}{2} - 1009 ^{2}$

$1009(1010 - 1009)$

$= 1009$