Question

Suma primelor 100 de numere nat impare

Answer 1

Suma celor 100 de nr. nat. impare este :
1+3+5+...+199
N= (199-1):2+1
N=198:2+1
N=99+1
N=100
S=(U+P)xN:2
S=(199+1)x100:2
S=200x50
S=10000

Answer 2

1+2+3+..........+99=.

1+2+3............+(2n-1)=n²

1+2+3+..........+99=2500

2n-1=99
2n=99+1
2n=100
n=50
1+2+3............+99=50²=2500