Automatic calculation for multiple $ denominations in 1 cell

I am pretty new to using excel. I am trying to create a spreadsheet for my finances. I am going to make a budget and I am planning on going to the bank each week and taking out a certain amount of bills. For example if my Gas is $75, I will need to take out 3-$20's, 1-$10 and 1-$5 to make up the $75. I want to put these amounts next to the total amount of the bill and then figure out a way to have the excel automatically calculate the column to show me at the end of the budget how many $20's, $10's and $5's I will need to take out. Is there a way to create an equation that can differentiate the different denominations like this?