# Maths

19.01.21

Today we are going to look at roman numerals.

Roman numerals we used in ancient Rome. They used letters to represent numbers. You may still see roman numerals around today. Here are a few places:

Clocks – time

End of programmes on tv – Date

Buildings – Show when they are built – Date

Royalty – E.g. King Henry VIII

They used 7 letters to represent different amounts.

Here they are: Now these letters can be arranged in different orders to make any number they needed to use.

Now being able to read numbers can become very tricky.

Here are 3 rules that explain how they work

• When a symbol appears after a larger (or equal) symbol it is added
• Example: VI = V + I = 5 + 1 = 6
• Example: LXX = L + X + X = 50 + 10 + 10 = 70

• But if the symbol appears before a larger symbol it is subtracted
• Example: IV = V − I = 5 − 1 = 4
• Example: IX = X − I = 10 − 1 = 9

• Don't use the same symbol more than three times in a row

Here are some more examples.

XLVII = L - X = 50 - 10 = 40

= V + I + I = 5 + 1 + 1 = 7

= 40 + 7 = 47

XLVII = 47

CCLXXXVI =  CC = 200

LXXX = 80

VI = 6

CCLXXXVI = 286

Remember if a letter representing a a smaller number comes before a bigger number you subtract. Bigger before smaller you add.

Using what you know now, go onto Purple mash and complete the 2do that has been set. Mr Hindman is always on Purple Mash for you to email and ask for help.

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