Question

1+2+3...100 va rog frumos

Answer 1

1+2+3+...+100=
100*(100+1):2=
100*101:2=
10100:2=
5050

Answer 2

$\displaystyle 1+2+3+...+100= \frac{100(100+1)}{2} = \frac{100 \times 101}{2} = \frac{10100}{2} =5050$