Question

1+2+3+4+..............+40=
1+2+3+.............+50=
1+2+3+.............+100=
5+6+7+............+80=
sama jalannya
semuanya

Answer 1

Gunakan gauss :

1+2+3+4+...+40 = (1+40) . 40/2 = 41 . 20 = 820
1+2+31... + 50 = (1+50) . 50/2 = 51 . 25 = 1275
1+2+3+... + 100 = (1+100) . 100/2 = 101 . 50 = 5050
5+6+7+... + 80 = (5+80) . 76/2 = 85 . 38 = 3230