Question

Care este suma numerelor naturale care impartite la 7 dau catul 12?

Answer 1

$restul\ \textless \ impartitorul \\ restul\ \textless \ 7 \\ restul$∈$(0,1,2,3,4,5,6)$
$7*12+0=84 \\ 7*12+1=85 \\ 7*12+2=86 \\ 7*12+3=87 \\ 7*12+4=88 \\ 7*12+5=89 \\ 7*12+6=90 \\ 84+85+86+87+88+89+90=609$