Question

tinh

2+4+6+8+.............+100

Answer 1

\(2+4+6+8+...+100\)

\(=2.\left(1+2+3+4+...+50\right)\)

\(=2.\frac{50.\left(50+1\right)}{2}\)

\(=50.51\)

\(=2550\)

Answer 2

= [(100 - 2): 2 + 1] x (100+2)

= 50 x 102

= 5100