Question

Dau coroana
1+2+3+...+105=
4+8+12+...+136=
5+10+15+...+110=
6+12+18+...+258=

Answer 1

$1 + 2 + 3 + ... + 105 = \\ \\ = \frac{105 \times 106}{2} = \\ \\ = \frac{11130}{2} = \\ \\ = 5565$

$6 +12 + 18 + ... + 258 = \\ \\ = 6(1 + 2 + 3 + ... + 43) = \\ \\ = 6 \times \frac{43 \times 44}{2} = \\ \\ 6 \times \frac{1892}{2} = \\ \\ = 6 \times 946 = \\ \\ = 5676$

restul sunt in poză

BAFTĂ!!!