残高, 収入, and 支出: a balance and incoming or outgoing money
Separate an account balance from incoming and outgoing amounts, reading a hypothetical balance change with no other changes.
The balance at the time checked
残高, read ざんだか, means the amount remaining in an account or similar record. 支払いの前に口座の残高を確認した。 reports checking the account balance before payment.
The checked balance and the amount to be paid are different items. The sentence does not establish that payment has already occurred.
Incoming and outgoing amounts
収入, read しゅうにゅう, is incoming money; 支出, read ししゅつ, is outgoing money. This example stipulates that both amounts are deposited into or withdrawn from the same account.
In the hypothetical record 残高は三千円です。千円が入り、五百円が出ました。, no other changes leave a balance of 3,500 yen. The one-thousand-yen incoming amount is not the entire balance.
Separate the roles of the amounts
残高を確認しましたが、支出はまだ記録していません。 says that the balance was checked but expenditure has not yet been recorded. The completed actions differ.
For a balance comparison, check the time of the value and the actual deposit or withdrawal conditions. This example does not establish that every income item enters the same account.
With a balance of three thousand yen, one thousand coming in, five hundred going out, and no other changes, is the new balance one thousand yen?
Show the answer and why
No. It is 3,500 yen. One thousand is the incoming amount, not the account’s entire balance.