Show remainder of Total amount when allocating to multiple transaction lines

When I am allocating a transaction retrieved from my Bank and allocating it to existing transactions, I should also see the remainder amount as I keep on allocating transactions to it where the total of the allocation is lesser than the total of transaction from Bank.

Example: a transaction downloaded from Bank has a total of $100

You've allocated a transaction which is $50, next to total (as a suggestion), it could show: "Remaining: $50".

If you allocate another transaction of $20 then it should say "Remaining: $30".