Question

1+2+3+.................+100

 

Answer 1

=\(\frac{100\cdot\left(100+1\right)}{2}=5050\)

Answer 2

Tu 1->100 co:(100-1):1+1=100(so)

1+2+3+...+100=(100+1)x100:2=5050

Cach lam: tim so cac so hang roi lay so cuoi cong so dau nhan so cac so hang chia 2 

luu y:

cong 1 la co dinh 

chia 2 cung co dinh

Answer 3

1 + 2 + 3 + 4 đến 99 + 100 ...

 Dài dòng quá !