Such a coin does not exist. The 5 and 10 New Pence coins were first introduced in 1968. The 50 New Pence coins were first introduced in 1969. The 1/2, 1 and 2 New Pence coins were first introduced in 1971.
British currency currently in circulation -One pennyTwo penceFive penceTen penceTwenty penceFifty penceOne poundTwo poundsFive Pound coins (occasionally seen in circulation)Five Pound noteTen Pound noteTwenty Pound noteFifty Pound note
British coins currently in circulation and worth less than 1 Pound GBP are - 1 Penny 2 Pence 5 Pence 10 Pence 20 Pence 50 Pence
Assuming that you refer to British coins, the 1991 5, 10 and 50 Pence coins are no longer in circulation and have little or no value. The 1, 2 and 20 Pence coins and the One Pound coins are still in circulation and are worth those amounts respectively.
There are 100 pence in a pound. Multiply by 100
You do not specify which coin. The 1 and 2 New Pence coins are still potentially in circulation, so are worth 1 and 2 Pence respectively. The Half, 5, 10 and 50 New Pence coins have long since been withdrawn from circulation and demonetised. Unless they are in mint condition, they are worth little or nothing.
The British two pence coins issued from 1971 through 1992 are bronze, 25.91mm in diameter, and weigh 7.12 grams. Composition was changed in mid 1992 to copper-plated steel (although there do still seem to have been some bronze coins issued through 2000), which are 25.86mm in diameter and weigh 7.14 grams.
A current 1p coin weighs 3.56 g £1 = 100p → a pound of penny coins weighs 3.56 g x 100 = 356 g
1 x 5 Pence coin plus 7 x 1 Penny coins = 12 Pence. 6 x 2 Pence coins equals 12 Pence.
7 x 2 Pence coins and 1 x Penny.
A 20 pence and a 5 pence. One of them is not a 5 pence.
The two coins are a ten-pence coin and a one pence-coin. The one-pence coin is the one that is not a ten-pence coin.