Answer
$3$
Work Step by Step
$\sum ^{6}_{k=1}\left( -1\right) ^{k}\times k=\left( -1\right) ^{1}\times 1+\left( -1\right) ^{2}\times 2+\left( -1\right) ^{3}\times 3+\left( -1\right) ^{4}\times 4+\left( -1\right) ^{5}\times 5+\left( -1\right) ^{6}\times 6=\dfrac {65}{}+4-3+2-1=3$
