Question

1. Calculati (prin metoda lui Gauss):
a) 1+3+5+...+99=
b) 5+10+15+...+2000=
c) 3+6+9+12+...+2001=

Answer 1

(1+99)x99:2=(100x99):2=199:2=99,5

2)5(1+2+3+....+400)=5x(400x401):2=401.000

3).3(1+2+3+4.....667)=3(667x668):2=(3x445556):2=668334

Answer 2

b)2(1+2+3+...+400)=
2(400*401):2=
400*401=
160400

c)3(1+2+3+4+....+667)=
3(667*668):2=
3*445556:2=
668334