Students learn about ordinals and Roman numerals.

Learning aims

• Learn about ordinals and Roman numerals in texts.

• Change numbers into ordinals and numerals.

Ask the class about the numbers used to describe Mickey Mouse's 75th year or Friday the 13th.

• What does the 'th' mean?
• Where do you think these 'ordinals' come from?
• Can you think of other ways of describing an order?

Roman numerals use letters in place of numbers:

1 = I 2 = II 3 = III 4 = IV 5 = V 6 = VI 7 = VII 8 = VIII 9 = IX 10 = X 20 = XX 30 = XXX 40 = XL 50 = L 60 = LX 70 = LXX 80 = LXXX 90 = XC 100 = C 500 = D 1000 = M

A number placed before a larger one can have the effect of minus.

So IV is four, five minus one, athough it is also often written as IIII.

Main activity
Display the following numerals and have students convert them into numbers.

CCXXVI = 226
XXXIV = 34
LXXIII = 73
CI = 101
VIII = 8
LVII = 57
MXII = 1012
XCII = 92
XV = 15
DXLIX = 549

When completed students should put these numerals in order from smallest to largest.

Explain that an ordinal names a position in a sequence eg: first, second, third etc.

Students write by their correct order the ordinal words for each position.

Plenary
Recap on the main teaching points and types of ordinals and numerals.

Teachers' Background
The origins of ordinal numbers:

First: This comes from the Old English 'fyrst'. This survives today in 'foremost'. The -st is actually a superlative ending (like "-est").

Second: This comes from the Latin 'secundus', meaning 'following' or 'next'.

Third: This comes from the Old English 'thridda'.

The other ordinals are believed to follow on in a similar way.