Want to limit amount taken out by a cell to a set amount. Still looking for help with this

Hello,

Making a new spreadsheet.

Would you please let me know how I can make a spreadsheet do this.

Nothing that I have tried is working so far.

A = $ 100
B = takes 100 % of the amount in A up to $ 40
C = takes 100 % of the amount in A up to $ 40
D = takes 100 % of the amount in A up to $ 20
E = takes 100 % of the amount in A up to $ 20 but does not post a value in the cell as there is nothing left of the $ 100.
etc.

Thank you,
Richard Todd