calculate rows and then show as 1 row.

I am trying to figure out the best way to calculate multiple rows, then have have it update as 1 row once calculated. 

So in the example in the pic,  I want to look at column A, and anything with the same number, take column B and calculate the total, update the first line, then remove the remaining.  

I'll have to do this weekly, so any automation tricks would be nice  

Thanks for your help!