Roman numerals · Usually met around P3
Roman numerals to XII and clock faces
Find the V or X, then see if the I is before or after it.
How to do it
Method
Find the V or X, then see if the I is before or after it
VII = 5 + 2 = 7; IX = 10 − 1 = 9
Another way
Landmarks
VIII: from V (5) count on 3 → 8
In full
Roman numerals use letters for numbers: I is 1, V is 5, X is 10. The same letter repeated adds: II = 2, III = 3. A smaller letter to the right of a bigger one adds too: VI = 5 + 1 = 6, XII = 10 + 2 = 12. An I to the left of V or X takes away: IV = 5 − 1 = 4, IX = 10 − 1 = 9. To read one, go left to right adding, and take away when a smaller letter comes before a bigger one. Or find the V or X as a landmark and see how many I's are before or after it: VII is 5 and 2 more, 7. On a clock face the numerals sit where the ordinary numbers do: XII at the top, III on the right, VI at the bottom, IX on the left.
Worked examples
Have a go first, then open each one for the answer and the working.
Example 1
The tablets count on in Roman numerals, 1 more each time. What number does “?” stand for?
Show the answer and working
Answer: 7
The first tablet is 6 and each one after is 1 more: “?” is tablet 2, so it stands for 7.
Example 2
This tablet has □ X's, □ V's and □ I's, and it stands for □.
Fill in each box
Show the answer and working
Answer: 0，1，2，7
Count each letter, then add left to right; an I before V or X takes away: 7.
Example 3
The number on the left tablet is bigger than the one on the right.
True or false?
Show the answer and working
Answer: False
Read both first: the left is 1 and the right is 7. Don't go by how many letters: VIII has four letters but is less than IX.
Practise it in the game →Roman numerals · Free to start, unlimited questions, no download