① You can calculate the supply price and value-added tax (tax amount) using only the total amount.
② You can calculate the value-added tax (tax amount) and total amount using only the supply price.
③ You can calculate the supply price and total amount using only the value-added tax (tax amount).
You can calculate ① the supply price and VAT only from the total amount, ② the VAT and total amount from only the supply price, and ③ the supply price and total amount from only the VAT.