Including Counted Value when Exceeding Threshhold

Hello,

This is my first post, so I apologize for any errors.

I have a problem I'm struggling to solve with inventory. I'm counting a quantity of a part where I need a certain amount.

Let's say I need 60 parts, and the first one I count has 30, then the next has 50, leaving me with 80. I need to use both of those since they total up to 60, but have some extra. I would not be able to use just the first count.

Is there a way to signify that I still need the count of 50 in this example? Such as call these "needed", then anything after "Extra".

Any help is appreciated. Thanks!