It's the same as English.
cinquante pence
trois livres et cinquante pence
2 pence.
peniques
six livres et quatre vingt dix neuf pence
2 pence.
When Australia used Pounds, Shillings and Pence, it was pronounced "pence", the same as in Britain where the currency originated. Since the 14th of February, 1966, Australia has used Dollars and cents.
Pence is the plural of Penny, so you have One Penny or, Two Pence, Five Pence, Fifty Pence, etc. From the introduction of British decimal coins in 1968, the new currency was designated as "New", ie. 1 New Penny, 2 New Pence, etc. until 1981. From 1982 onwards, the "New" was dropped.
Occasionally, the Royal mint has a mix up with the dies or the blanks used to produce coins. It is possible that the 10 New Pence dies were used on a 2 New Pence blank. If this is the case, part of the 10 Pence coin design will be outside the perimeter of the 2 Pence blank, the 10 Pence coin being slightly larger than the 2 Pence coin. Alternatively, you may have a trick coin available from magic shops.
2 pounds and 99 pence for a cheeseburger and 12 pounds for a french fry.
Pence is the plural of Penny. 1 Penny, 2 Pence, 3 Pence, 10,938,451,117 Pence.
12% of 50 pence= 12% * 50 pence= 0.12 * 50 pence= 6 pence