The general formula for this is:
An = A1 + (n-1)d
Where:
An= The nth term
A1= 1st term
d= Common difference
n = # of terms
So in your case: A1 = 10, d = 4, and n =5
An = 10 + (n - 1) * 4 = 10 + 4n - 4 = 4n + 6
Try n=1 : A1 = 10, n=2: A2=14, ... n=5: A5=26.
I hope that helped!
