±«Óătv

Watch: Analogue and digital time

There are 24 hours in one day, but the day can be measured by splitting it into two halves.

The first 12 hours of the day - from midnight to midday - are called AM, and the next twelve hours are called PM.

Back to top

Roman numerals

The Roman numeral XII, meaning 12, next to a brain
Image caption,
X is 10, so XII is 10 + 2, or 12

The Romans used a different numbering system from the one that we use today. Their numbers were shown by letters.

I = 1, V = 5, X = 10, L = 50 and C = 100

Here are some examples.

V is 5, so VI is 5 + 1 or 6

IV is 4. When the I is before the V it means 1 less than 5

The Roman numeral XII, meaning 12, next to a brain
Image caption,
X is 10, so XII is 10 + 2, or 12
Back to top

Activity 1

Back to top

Activity 2

Back to top

Activity 3

Back to top

Quiz

Back to top

NEW! Play Guardians: Defenders of Mathematica - the Halloween update. game

Experience Mathematica as you’ve never seen it before, with all-new backgrounds and costumes for Halloween. Available for a limited time only. Use your maths skills to save the day before it's too late!

NEW! Play Guardians: Defenders of Mathematica - the Halloween update
Back to top

More on Measures

Find out more by working through a topic