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Positional notation

math Maturity 7-9 Next article →

Imagine looking at the number 5. Now look at the number 50. The digit looks exactly the same, but the second one is much larger. This happens because of positional notation. In this system, the value of a symbol depends on its position. Each place represents a power of a fixed base.

Positional notation glossary-en
Positional notation glossary-en

This makes math much easier to do. It is much faster than older ways of writing numbers. This is why this system spread so quickly across Europe.

Most people today use the Hindu-Arabic system. This is a base-ten system. It uses ten distinct digits from zero through nine. Each symbol's value is the digit multiplied by a power of ten. For example, in the number 465, the 4 is in a place worth hundreds. If we used base seven, the places would change. In base two, which is called binary, we only use two digits.

Chounumerals
Chounumerals

Computers use binary because it works well with electronic circuits. A radix point, like a decimal point, helps us write fractions too.

Long ago, people used additive systems instead. In Roman numerals, you just add the values of the symbols together. For example, the number 14 uses two copies of a symbol for ten. It also uses four copies of a symbol for one. The Babylonian system was the first positional system. It used a base of sixty.

abacus 6
abacus 6

This system still affects us today. We use sixty minutes in an hour and 360 degrees in a circle. Even the Inca used a positional system with knots on cords called quipu.

History shows many clever people working on these ideas. The Chinese used rod numerals as early as the 8th century. Around 700 BC, the Babylonians began using a placeholder for zero. This helped people tell the difference between numbers like 2 and 120. The mathematician Archimedes even invented a decimal system based on 108. In the 10th century, Abu'l-Hasan al-Uqlidisi used decimal fractions in Damascus. Later, Simon Stevin helped make decimal fractions common in Europe.

abacus 6
abacus 6

Positional notation connects to many things you see every day. You use base ten when you count on your ten fingers. You see the base sixty system every time you look at a clock. When you use a calculator, you are using binary logic. Even the way we measure weight and distance uses these ideas. It turns a hard job into a simple one. It allows us to represent any number with great accuracy. This system is a tool that helps us understand the whole world.

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File:Positional notation glossary-en.svg
Positional notation glossary-en.svg
File:abacus 6.png
abacus 6.png
File:Chounumerals.svg
Chounumerals.svg
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