👤

CALC
4+8+12+...+364=
12+13+14+...+50=
8+9+10+....+70=
RAPID




Răspuns :

4+8+12+...+364=
4×(1+2+3+...+91)=
1+2+3+...+91=
(1+91)×91:2=
92×91:2=8372:2=4186

12+13+14+...+50=
(12+50)×38:2=
62×38:2=2356:2=1178

8+9+10+...+70=
(8+70)×62:2=
78×62:2=4836:2=2418