Question

(-1)+(-3)+(-5)+...+(-197)+(-199)

Answer 1

\(\left(-1\right)+\left(-3\right)+\left(-5\right)+...+\left(-197\right)+\left(-199\right)\)

\(=-\left(1+3+5+...+197+199\right)\)

\(=-\dfrac{\left(199+1\right).\left[\left(199-1\right):2+1\right]}{2}\)

\(=-\dfrac{200.100}{2}=-10000\)

Answer 2

(-1)+(-3)+(-5)+....+(-197)+(-199)

=-(1+3+5+....+197+199)

Số hạng :-(199-1):2+1

=-100

Tổng:(199+1)×-100:2

=-10000