You can
put this solution on YOUR website!
(1+i)+(3+i) = 1+i+3+i = 1+3+i+i =(1+3)+(i+i) =
(4)+(1i+1i) = 4+i(1+1) = 4+i(2) = 4+2i
or do some of all of those steps in your head.
You can do it all in one step.
(1+i)+(3+i)
Just add the red numbers 1+3 in your head, getting 4.
Then add the blue letters i+i getting 2i.
Then just write 4+2i all in one step.
Edwin