LearningAim Objectives • Learning other numeral systems. • Learning the Roman numeral system and understanding how it is currently used. • Remembering another numeral system, such as the Egyptian one. SuccessSuccess Criteria Criteria • Statement 1 Lorem ipsum dolor sit amet, consectetur adipiscing elit. • I can write Roman numerals. • Statement 2 • I can recognise features of Egyptian numerals. • Sub statement In Ancient Rome In Ancient Rome, people used letters rather than numbers to write dates. Look at the image on the right: They used the following rules: 1. The numbers I, X, C and M are the only ones that can be repeated two or three times: III = 3 CCC = 300 XX = 20 MM=2000 2. If we place a letter to the right of another letter of equal or higher value, we add them together. For example: XII = 10 + 2 = 12 DC= 500 + 100 = 600 LV= 55 CX=110 In Ancient Rome 3. If we place the letters I, X and C to the left of another of equal or higher value, we subtract them. For example: IX = 10 – 1 = 9 XL = 50-10= 40 -The letter I can only be subtracted from V and X. -The letter X can only be subtracted from L and C. -The letter C can only be subtracted from D and M. 4. A horizontal line on top of the letter indicates that we must multiply it by a thousand. We therefore add three zeros. For example: XI = 11,000 CD = 400,000 XL = 40,000 Interesting Facts About Roman Numerals Although in present Rome they use the same numbering system that we currently use, Roman numerals are still used to indicate centuries (21st century is thus written XXI secolo). Roman numerals are also used as regnal numbers, being placed next to monarch names (such as in Elizabeth II). Some clocks have the number IIII instead of IV. This is because IV used to be considered unlucky since it was associated with the name of Jupiter, the Romans’ supreme god (written IVPITER). That is also why we can see some ancient gravestones with the number IIII instead of IV. There was no zero in Ancient Rome, so there is no Roman numeral for that number. In Ancient Egypt Antient Egyptians wrote using They used an additive system of hieroglyphs. Hieroglyphs were numbers, which means that the values also used to write numbers. of each hieroglyph are added to obtain the final number. What number is this? 13,031 = 10000+3000+30+1 Up until 2000 BC, Egyptians did not use the number zero either. They invented the number zero along with negative numbers for architectural purposes, especially to build the great pyramids. Do you know the names of these pyramids? In this image we can see how the Egyptian numeral system works. Can you see it? When Romans arrived in Egypt, the Egyptian numeral system was abandoned and, to the great relief of the scribes (the people who wrote and copied documents), the Roman numeral system was adopted. Yet, as we have seen, the Romans did not use the number zero or negative numbers. Isn’t it curious? What do you think? The pyramids of Khufu, Khafre and Menkaure. The Egyptians, like the Romans after them, expressed numbers according to a decimal scheme, using separate symbols for 1, 10, 100, 1,000, and so on; each symbol appeared in the expression for a number as many times as the value it represented occurred in the number itself. Can you make the number 24? Calendar system Now we are going to look at how the Egyptians and Romans have adapted and developed the calendar system. What is interesting is that the calendar we use today is over 2000 years old! Calendars In the Egyptian era calendar days were 365 days long, there were 12 months which consisted of 30 days. There were 3 seasons. Adaptations to the calendar system In 30 BCE the Roman Emperor Augustus reformed the Egyptian calendar by adding a leap day to every fourth year. This brought the Egyptian calendar in line with the Julian calendar used at the time in Rome. What do you notice by looking at the Emperors name? How did you do? Januarius Februarius Martialis Aprilis Maius Junius Julius Augustus September October November December How have the Romans and Egyptians helped us? What did you use to help you? What is same/different about the month names now? Why were some of the names changed such as mars and March. Why do you think we don’t refer to names of months as they are on the Roman calendar? .