WORLD HISTORY READERS Level 1-⑧ The Magic of Numbers

Using Your Fingers How did people discover numbers? From the beginning, people probably used their fingers to show numbers. But there are only five fingers on each hand. How did people discover numbers? What happens if you want to say that you are eleven years old? We don't have enough fingers!

The First Numbers Who discovered the first numbers? We don’t really know who made it, but the Ishango bone is the oldest thing that shows counting. The Ishango bone was found in Africa and is around 22,000 years old. It has groups of marks on it. Each group has the same number of marks. So the people who made the bone were counting in units.

Egyptian Numbers How did the ancient Egyptians record numbers? The easiest way to write the number one is probably to draw something like a finger. This is what the Egyptians did. How did the ancient Egyptians record numbers? The Egyptian number one is represented by “I.” Their number two is represented by “II.” When they got to five, they wrote three marks and then two marks under them, so it was easy to read. Their ten looked a bit like an “n.”

Roman Numbers How did people in ancient Rome record numbers? The 2 = II 3 = III 4 = IV 5 = V 6 = VI 10 = X 17 = XVII 29 = XXIX 68 = LXVIII 273 = CCLXXIII 2516 = MMDXVI The Roman numerals How did people in ancient Rome record numbers? The Romans changed the Egyptian system. The Romans did not want to use too many marks. When they got to five, instead of writing it with five marks, they wrote it like this – “V.” Comparing the Roman and Egyptian systems

The Indian System Who discovered the system of numbers that we use today? Hindi numbers The people of India discovered the system we use today. They realized that it was easier if every number had its own symbol. So you can write numbers in a list like this: 1 = One 6 = Six 2 = Two 7 = Seven 3 = Three 8 = Eight 4 = Four 5 = Five 9 = Nine

The Number Zero Where did the number 0 come from? Why is 0 important? The discovery of the number zero was probably made by an Indian. Why is 0 important? Zero makes it very easy to write out large numbers like 1,000,000. It also makes math easier. Counting with the Hindi system is easy. We start with the first number on the right, which is the ones place. The second to the right is the tens place, the third is the hundreds, and so on.

An Asian Counting System What is an abacus? It a counting device that uses beads. Where is the abacus still used on a daily basis? East Asia! Some people are faster with it than with a digital calculator!

Nature’s Numbers What is the “golden ratio”? The “golden ratio” is a common number in nature. The first dimension is 1 and the next is 1.618 times that. This ratio appears in many things in nature, like flowers and shells. It is 1.618. A long time ago, people realized that the dimensions of many objects in nature are about 1:1.618. Do people use the “golden ratio”? Yes, we do. In fact, we find the “golden ratio” in everything we think is well-designed or beautiful.

Computers and Numbers How do computers count? Computers count in binary numbers: 1s and 0s. The sequence for 4-bit code is 0000, 0001, 0010, 0011, 0100, 0101, etc. Most computers now use 8 bits and can represent 256 values.

Yes! Birds notice how 3 and 4 are different. Animals and numbers Can animals count? Yes! Birds notice how 3 and 4 are different.

Vocabulary borrow v. binary adj. (a number system) with only two numbers: 0 and 1 borrow v. to use something that belongs to someone else and then return it to them

Vocabulary dimension n. mark n. a measurement of the length, width, or height of something mark n. a line or scratch

Vocabulary sequence n. notice v. to see something and be aware of it a series of numbers in order

Vocabulary shell n. symbol n. the hard outer covering of some creatures symbol n. a character or number that represents something else