Question

tính hợp lý :
A=1-3+5-7+9-11+...+99+101

Answer 1

\(A=1-3+5-7+9-11+...+99+101 \)

\(A=(1-3)+(5-7)+(9-11)+...+99+101\)

\(A=(-2)+(-2)+(-2)+...(-2)+101\)

\(A=( - 2 ) . 25 + 101\)

\(A=( - 50 ) + 101\)

\(A=51\)