# Math 11 Edublog post #1

This week I learned a lot of new things but one that stood out was finding out how to add up all the numbers in a arithmetic sequence. The formula we use is below.

$S_n=(t_1+t_n)\cdot (n\div2)$

In a sequence such as 1,3,5,7,9 to find $S_{23}$ you would have to use the above equation as well as and equation to find $t_{23}$ the solution is as follows in the picture of my work.