Roman numeral clock faces (2)

roman numerals clock 2Our Roman numerals clock face worksheet has proved very popular so I thought I would post another similar page, but including quarter to and quarter past the hour times. I have also been asked why the clock face shows IIII for four o’clock rather than IV. In fact most Roman clockfaces do show the four Is and nobody is sure why.

One reason is that when looking at the numerals opposite to each other – all of them are in perfect balance, except for the ‘heavy’ VIII and the ‘light’ IV; optical balance is re-established by printing an also ‘heavy’ IIII.

Another reason which has been given is to do with the old casting process of the numerals; ‘ Since some numerals were cast out of metal, or carved out of wood or bone, you need 20 I’s, 4 V’s, and 4 X’s, even numbers of each, if you use four I’s for “four”. The molds would produce a long centre rod, with 10 I’s, 2 V’s, and 2 X’s on each side.’

A third possibility is that clocks use IIII rather than IV out of respect for the Roman God Jupiter, the king of the Gods,  whose name, in Latin, begins IV (the V being the U we now use, the I the J). Very old sun dials seem to use the IIII and early clocks followed suit; it has also been suggested that Wells Cathedral clock, one of the earliest cathedral clocks used the IIII and everyone copied this, and yet another reason is that Louis XIV preferred IIII over IV and ordered all clocks to be made in this way, and it has remained like this ever since.

Finally it has also been suggested that Romans were not great at subtraction so IIII was easier to work out than IV! I have no idea which, if any of these has the best claim to being true but interestingly Big Ben uses the IV convention.

Roman numerals clock  2

Roman numeral clock faces

roman numerals clockOne of the new targets for maths in year 3 will be to, ‘tell and write the time from an analogue clock, including using Roman numerals from I to XII’. As I haven’t published any time sheets using Roman numerals I thought that now was the perfect opportunity; so here it is!
It is best that children are introduced to the Roman system of numbers before doing this worksheet, although it is interesting to understand that many adults do not look at the numbers around the clock, just the angle of the two hands and indeed many fashion watches fail to have numbers on at all, but we still manage to be able to tell the time.

This page sticks to just whole hours and half hours, although perhaps it should be pointed out that Julius Caesar and his chums would never had read the time in this way!!

Roman numerals: clock faces

Reading and writing Roman numerals

Reading and writing in Roman numerals is quite tricky and if you are thinking of doing addition and subtraction with them it is much easier to convert them, do the sum and then rewrite the answer in Roman letters.
The Roman system is based round 7 letters:
I = 1
V = 5
X = 10
L = 50
C = 100
D = 500
M = 1000

Interestingly there is no zero!
Numbers can be written by writing these letters, and then adding them up. So:
XVI is 10 + 5 + 1 = 16.
There are a few rules to follow:
1. It is possible to repeat a letter many times (xxxx = 40) but a general rule is that a letter can only be repeated three times.
2. If a letter is placed after a letter of greater value then add. eg VI = 5 + 1 = 105
3. If a letter is placed before another letter of greater value subtract that amount. eg IV = 5 – 1 = 4
Roman numerals are still used in certain circumstances. You may see them on a clock face, in an index or, probably most often used for the date at the end of a film or TV programme. These two pages of worksheets explore some of the easier aspects of reading and converting Roman numerals.

These worksheets can be found in the Year 6 Understanding Number category.

Reading and writing Roman numerals