Question

1+(-2)+3(-4)+...+99+(-100)

Answer 1

\(1+\left(-2\right)+3+\left(-4\right)+...+99+\left(-100\right)\)

\(=\left(-1\right)+\left(-1\right)+...+\left(-1\right)\)

\(=\left(-1\right).50\)

\(=-50\)

Answer 2

1+(-2)+3+(-4)+....+99+(-100)

=[1+(-2)]+[3+(-4)]+...+[99+(-100]

=(-1)+(-1)+...+(-1)+(-1)

=(-1)×50

=-50