Question: My savings account had an opening balance of ₹25,000 on the 1st of the month. During the month: a debit of ₹4,000 on the 3rd, a credit of ₹15,000 on the 7th, a debit of ₹2,500 on the 12th, a credit of ₹6,000 on the 18th, and a debit of ₹9,000 on the 25th. Assuming a 30-day month with no other transactions, what was my closing balance, and what was the lowest balance the account touched at any point?
Answer: Closing balance = ₹30,500. Lowest balance during the month = ₹21,000 (from the 3rd to the 6th, before the 7th credit).

Supporting evidence:
title: Inline formula / method note
quote: Basic bank account ledger arithmetic and running-balance reconciliation
context: Basic bank account ledger arithmetic and running-balance reconciliation.