Base 10

Base 10 refers to the place value number system that uses decimal numbers and is commonly used worldwide. It is the basis of a place value number system called the decimal or denary system.

What is base-10?

Have you used numbers 0 – 9 to count? Then without even realizing it, you’ve used base-10!

Base 10 is a method of assigning a place value to numbers. It’s also known as the place value number system or decimal system, as the numerical value of a number relies on where the decimal point sits. In base 10, each digit in a place of a number can have an integer value ranging from 0 to 9. This system uses ten as its base number, which is why it is called the base-10 system. Base-10 blocks help children experiment with essential addition and subtraction within the realms of base-10.

Base 10 describes how much value each digit has in a whole number.

Each number = 10x the value to its right. For example:


Within this large number, each digit has a value of:

3 has a place value of 300,000 (three hundred thousand)

4 has a value of 40,000 (forty thousand)

5 has a value of 5,000 (five thousand)

8 has a value of 800 (eight hundred)

6 has a value of 60 (sixty)

2 has a value of 2 (two)

1 has a value of 1/10th (one-tenth)

2 has a value of 2/100th (two one-hundredths)

5 has a value of 5/1000th (five one-thousandths)

Why do we use base-10?

Numbers 0,1,2,3,4,5,6,7,8 and 9 are the digits before 10, a number with more than one digit to define it. Using extra digits at the end of a number represents how many times we have run out of that particular digit. It is known as the place value number system.

Numbers that are bigger than 1 and are on the left side of a decimal point will fit into the following place values:

  • Ones (1).
  • Tens (10).
  • Hundreds (100).
  • Thousands (1000).
  • Ten thousand (10,000).
  • Hundred thousand etc. (100,000).

If they are to the right of a decimal point, the place value appears differently:

  • Tenths (10th).
  • Hundredths (100th).
  • Thousandths (1000th).
  • Ten Thousandths (10,000th).
  • Hundred thousandths etc. (100,000th).

The creation of base-10:

The use of Base-10 goes back to ancient civilizations. 10 was the best number to use as a base for counting, as humans have ten fingers. Counting using fingers has been a method of simplifying counting for thousands and thousands of years. In Ancient Egypt, a decimal system was prominent. Still, the Ancient Greeks and Romans took this knowledge and developed it into a base-5 system, which allowed mathematicians to count using only one hand.

Other countries previously used base-20 (using all fingers and toes to count). It is where base-10 developed and why it’s taught globally to help

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