👤

(14 Calculati:
a 1+ 2+ 3+ 4+ 5+ 6+ 7;
b 10 + 20 + 30 + 40 + 50 + 60 + 70;
d 11 + 12 +13 + 14 + 15 + 16 +17+18.
c7 +14+ 21 + 28 + 35 +42;​