Zaira spent 55 hours in 2 weeks working on a science project. she worked 32 hours the first week. write and solve an addition equation to find the amount of time she spent working the second week.

What do we know? 
55 hours in 2 weeks
32 hours in the first week
So, 32 plus the amount of time she worked on the project the second week adds up to 55.
32 + x = 55
Now, simply solving! What you do to one side, you do to the other in order to isolate the variable
(32 - 32) + x = (55 - 32)
x = 23 
She worked 23 hours on the project during the second week!