Roman Numerals

Roman Numerals

Poll

Do you know what Roman Numerals are?

• Yes

• No

Let's Look At Some

Obviously, this is a list of Roman Numerals from 1-100.

So why did the Romans need a number system?

• Just like us... they needed to count things.

• The numerals developed out of a need for a common method of counting, essential to communications and trade.

• Yes, they could count on their fingers. But once you reach 10, you can start to get confused.

Why the goofy lines and letters? How did they get the symbols as numbers?

• The main few symbols of counting are: a single line to represent 1 unit, a V to represent 5 units, and X to represent 10, and the larger symbols came from their language.

Say you are counting the number of crates coming off a ship.

• Hold up your hand and count to 5.

• The single line to represent 1 comes from your fingers

• The V to represent 5 comes from your pointer finger and thumb. It looks like a V so that was now the symbol.

• Now count to 10 using both hands. What happens when you overlap your thumbs? Yep, an X!

• With a system to count and keep track of objects, you now can keep track of things by writing them down

• To continue with the crates example. Say you ordered 17 crates. Before this system, one could have got forgotten, maybe the trader sold it to someone else.

• This system keeps people acCOUNTable

Rules

• The numerals are placed left to right. Depending on their placement add or subtract the values.

• If one or more letters are placed after a letter of greater value, you add. (III would be 3, adding them)

• If a letter is placed before a letter of greater value, you subtract. (IV would be 1 less than 5, so 4)

More Rules

• You can only use a symbol three times. That means 4 is not IIII but IV

• Only one number can be subtracted from another. So, 13 is not IIXV. It's easy to see how the reasoning would be: 15 minus 1 minus 1. But following the rule, it instead is XIII, or 10 plus 3.

• Oh, and there is no number for 0!

Open Ended

Do we still use this number system? If so, where?

Bam.. look at that. Roman Numerals!

More Roman Numerals.

Every movie is copyrighted with Roman Numerals!

They are even on our money!!

Other Places

• Kings, Rulers, Popes, Queens, etc. (King George III)

• Watches and clocks

• Books and chapters

• If a father has a son, they become a Jr. or a II. The line could continue to the third son becoming the III.

• Olympics and other sporting events.

Why do we care about Roman Numerals?

• Even though we have a much better (and easier) number system now, we still use Roman numerals all the time

• We like they way they look and they do they same thing as our number system