What is the sum of three consecutive natural numbers? 1+2+3=6 Discovery: (1+3)× 3÷2

What is the sum of four consecutive natural numbers? 1+2+3+ 10 Discovery: (1+4) × 4÷2

……

What is the sum of ten consecutive natural numbers? 1+2+3+4+5+6+7+8+9+10 = 55 Discovery: (1+10) ×10 ÷ 2.

General:

What is the sum of several consecutive natural numbers?

There can be (the first number+the last number) × * * * ÷2= the sum.

That is, the summation formula of natural numbers: (first term+unfinished term) × number of terms ÷2= sum.

This is from special to general.