Cannot update the record in table by form

[Guest]

I have two tables,
Table 1: 10 Account with the own balance
Table 2: When i createnew record for it Account, it Account balance is
reduce by my amount enter in that new record.
i.e Account A original have $10, new record for Account A = $ 2, new Balance
in Table 1 for Account A is $8

I had try to make a Query and attached with a Marco for that, but how can I
replace the original balance to new balance each time after I run that Marco?
Please help.
many thanks

 

[nanne]

Why change the balance in your tables every time.
Balance is a calculation of the transactions
use formula" =som([amount]) " in a query or form.