Question

Calculati suma resturilor posibile ale impartiriiunui numar natural la 19

Answer 1

$D: I= C+R \\ R\ \textless \ I \\ \\ D:19=C+R \\ \\ R\ \textless \ 19 \\ R- NR . NATURAL=\ \textgreater \ R= [1,2,3,4....,18) \\ S= 1+2+3+...+18 \\ S= \frac{(1+18)*18}{2} =19*9=171$