Question

2+4+6...+100= Va rog frumos explicatimi bine multumesc

Answer 1

$\displaystyle 2+4+6+...+100=2(1+2+3+...+50)=2 \times \frac{50(50+1)}{2} = \\ \\ =2 \times \frac{50 \times 51}{2} = \not 2 \times \frac{2550}{\not 2} =2550$

Answer 2

suma gauss
seda factor comun 2
2(1+2+3+....50)=2x50x51/2=2550