How much is 1 added to 100? Is there a simple formula?

How much is 1 added to 100? Is there a simple formula?

This is an arithmetic sequence
Because the difference between the latter and the former is the same
Gauss formula: the first term plus the last term multiplied by the number of terms divided by 2
1 + 2 +3+…… +100
100+99+98+…… + 1
Add up and down
Each item is 101
A total of 100 items
It's the sum of two sequences
Divide by two
（1+100）×100÷2=5050

What is the simple formula of adding one from two hundred to one hundred?

(1 + 100) * 50, because 1 and 100, 2 and 99, 3 and 98 So the answer is 5050
From one to two hundred, it can be calculated as: (1 + 200) * 100, which is 20100

1 + 2 + 3 + 4 (. 100) = simple algorithm

1+99+2+98+.+49+51+100+50
=100*50+50
=5050