We write numbers using only ten symbols (called Digits).
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Where we place them is important.
The Ten Digits
The Digits we use today are called “Hindu-Arabic Numerals”:
We can use these on their own to count up to 9:
0 | |
1 | |
2 | |
3 | |
4 | |
5 | |
6 | |
7 | |
8 | |
9 | |
?? |
But what happens after 9?
Ten Or More …
When we have more than 9 items, we start another column – the “tens” column – and we write down how many “tens” we have, followed by how many “ones” (also called “units”).
So we write:
10 |
It says we have 1 Ten and 2 Ones, which makes 12.
This can also be written as 1 × 10 + 2 × 1.
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We have to put a Zero in the Ones place or “10” looks like “1”.
A Hundred Or More …
When we have more than 99 items, we start another column – the “hundreds” column. Now we need to show how many Hundreds, Tens and Ones:

That shows we have 1 Hundred, 4 Tens and 3 Ones:
This can also be written as 1 × 100 + 4 × 10 + 3 × 1.
Example: “369” means 3 Hundreds, 6 Tens and 9 Ones
Which is also 3 × 100 + 6 × 10 + 9 × 1
And So On …
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Each time we want to show a bigger number we just add one column to the left and we know it is always 10 times bigger than than the column on its right.