On the page Settings > Prices and discounts, you can set the rounding of prices:
Round prices in Postings. To round prices during the posting of products (excluding the cost price).
Round the sum when depositing to the cashbox. To round any money deposited to the cashbox.
If you specify the number 1 in the field “Round to”, rounding will be performed to the whole number.
If you specify the number 10 in the “Round to” field, rounding will be done to a decimal.