Positional notation

Positional Notation

Positional notation is a fun way we write numbers. It means the value of a number changes depending on where each digit sits! For example, in the number 123, the “1” is in the hundreds place, the “2” is in the tens place, and the “3” is in the ones place.

We most often use a system called the Hindu–Arabic numeral system. This system uses ten symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9. It is a base ten system, which means each place shows a power of ten. The first place is ones (10⁰), then tens (10¹), then hundreds (10²), and so on.

Long ago, people used different ways to write numbers. The Babylonian numeral system used a base of 60. This is why we have 60 minutes in an hour and 360 degrees in a circle today! They did not have a symbol for zero, so they used a space to show an empty place.

Tools like the abacus helped people do math before we had our modern numbers. An abacus has beads that move to show numbers in a place-value system.

Today, computers use a system called the binary numeral system. This system uses just two symbols: 0 and 1. It is a base two system, which makes it easy for computers to understand with their on and off switches.

Our way of writing numbers makes math easier and is used all around the world. It helps us count, shop, and even tell time!