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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.

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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
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Activity 1

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Activity 2

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Activity 3

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Quiz

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

It's Mathematica as you鈥檝e never seen it before, with all-new festive backgrounds and costumes. 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 winter update
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More on Time

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