唔識sales 同purchases control account

Control means the total account. The sales control account will be debited, say, a month's sales and Cr. Sales while the individual trade debtor's account (Debtors' Ledger) will be debited with the amount of each invoice. The amount debited to the sales control account must ageed with the total of each debtor's account.
Purchase control is the other way round with the total purchase being debited ro Purchases Account and Cr. trade creditors in this control account. Individual creditor's invoice will be recorded in each of the creditors' account.