Question

Cum rezolv :3+6+9+12+.........57?

Answer 1

Suma lui Gauss :


3 + 6 + 9 + 12 + ........... + 57 =
3 • ( 1 + 2 + 3 + 4 + ........... + 19 ) =
3 • 19 • 20/2 =
3 • 19 • 10 =
57 • 10 = 570

Answer 2

3 + 6 + 9 + 12 + ........ + 57

3 ( 1 + 2 + 3 + ....... + 19 )

1 + 2 + 3 + ...... + 19

( 19 × 20 ) /2 = 190

190 × 3 = 570 ;