1956 Australian Pennies minted at the Melbourne Mint have no mintmark.
1956 Australian Pennies minted at the Perth Mint have a dot (.) after the Y in PENNY (PENNY.)
An Australian 1956 Penny looks almost exactly the same as any other Australian Penny minted from 1955 to 1964 inclusive. A 1956 Penny minted in Perth will have a mintmark (.) after the "Y" in PENNY (Y.). The Melbourne Penny has no mintmark. See the 1964 penny at the link below.
Australian Pennies from 1955 to 1964 inclusive were minted at either or both of the Melbourne Mint and the Perth Mint. Pennies minted at the Melbourne Mint have no mintmark. 1956 Pennies minted at the Perth Mint can be identified by a dot "." after the "Y" in PENNY, eg. "PENNY.".
Australian 1920 pennies were minted in both Melbourne and Sydney. On the reverse side underneath the word "PENNY", is a scroll. Coins minted in Melbourne will have a small dot under the scroll, coins minted in Sydney will have a small dot above the scroll. Some coins have no dot and could have been minted at either the Melbourne or Sydney Mints. The "no dots" coins are classified as rare. This means of determining the mint, only applies to 1920 pennies.
An Australian 1955 bronze Penny (Elizabeth II)(minted in Melbourne - no mintmark), uncirculated and in absolute mint condition could fetch up to $50 AUD. If it has been circulated but still in good condition, it might fetch anything from $0.75 to $8 AUD. There were 6.936 million minted. An Australian 1955 bronze Penny (Elizabeth II)(minted in Perth - mintmark = Y.), uncirculated and in absolute mint condition could fetch up to $65 AUD. If it has been circulated but still in good condition, it might fetch anything from $0.75 to $7 AUD. There were 6.202 million minted. An Australian 1955 bronze Penny (Elizabeth II)(minted in Melbourne - no mintmark)(Proof), could fetch up to $1,100 AUD. There were 1,200 minted. An Australian 1955 bronze Penny (Elizabeth II)(minted in Perth - mintmark = Y.)(Proof), could fetch up to $10,500 AUD. There were 301 minted. A reputable coin dealer will be able to give a more accurate valuation.
There were was no Australian 1956 Halfpenny minted.
There were no Australian Halfpennies minted from 1956 to 1958 inclusive.
There were no Australian Halfpennies minted from 1956 to 1958 inclusive.
4 or 5 cents. Over 1 billion of these coins were minted.
The US cent was first minted in 1793 and since then they have been produced in every year except 1815. At that time the blanks were made in England. None had been imported since the beginning of the War of 1812 and the supply finally ran out.
You do not specify a country. As far as coins are concerned, the terms "rare" and "valuable" are not the same thing and do not necessarily go hand in hand. There are no 1956 Australian, British or New Zealand coins that could be considered to be rare. Variants of the 1956 New Zealand Penny and Threepence are valuable. About 50,000 Pennies of a total of 3.6 million minted and 300,000 Threepences of a total of 4.8 million minted, were struck showing Queen Elizabeth II with a bare shoulder. These are referred to as the "strapless" coins. There was a similar "strapless" Sixpence minted in 1957. The greatest value is associated with mint uncirculated coins or coins in excellent condition.
A penny.
No. There were just under 421 million minted in Philadelphia, and 1.1 billion in Denver. It's actually the most common date for all 1950s wheat cents.