Hi, I'm sure this is simple for some, but it definitely has me stumped!

We receive loads of material that is sorted out and quantified as a percent of the total load in 5 categories. I then calculate out the weight of this percentage manually and enter it in each corresponding cell in a single row of data.

For example:
A1 = Total weight of load
A2 = category x
A3 = category y
A4 = category z and so on.

So if A1 = 2.5 tons, I input 2.5
If A2 is 40%, I manually multiply out 2.5*.4 on my calculator and enter that number in cell A2.

I would like to be able to just enter .4 or 40 in A2 and it calculate out 40% of A1 automatically. There is a lot of rows of info going into this sheet along with numerous other calculations, so to designate a separate cell for percentage and for it's resulting value wouldn't be helpful.

I hope this is described clearly, I would love some help, as a solution would greatly cut down on time devoted to this!