Arithmetic progression

[Palmeri]

Find the sum of the numbers
1 + 2 + 3 + ... + 100 = ?

Here a1=1,last term is 100 and number of terms are also 100
Therefore,
Sum of n numbers =n/2(first term +last term)
When we substitute we get
=100/2(1+101)
=50*101
=5050

Can anyone confirm if this is the right way to do it?

[rubyatiy]

Find the sum of the numbers
1 + 2 + 3 + ... + 100 = ?

Here a1=1,last term is 100 and number of terms are also 100
Therefore,
Sum of n numbers =n/2(first term +last term)
When we substitute we get
=100/2(1+101)
=50*101
=5050

Can anyone confirm if this is the right way to do it?

These are the search console and probably the time to justice with