[2Gkashmiri]

In manual system, we used to have a "page total" for a single page of a ledger/book so you just had to query last page total and bring that forward. In immutable ledgers, if you have a running total, the last balance is your current one.....

And you are certain about going 1 month (or period) going back that at a particular date, at he last entry the balance was something.

Same as in paper books. Just see page total of that particular date....