# Scientific Notation

## What Is Scientific Notation?

Scientific notation is a way of writing a number.

In scientific notation, a number is written as a number between 1 and 10 multiplied by a power of 10.

The number below is written in scientific notation. It is said as "1.2 times 10 to the 3".

### Dictionary Definition

The Oxford English Dictionary defines scientific notation as "a system of representing some given number as a product of a number with an absolute value between 1 and 10 and a power of 10 (as 2 × 10^{2} for 200)"

## Understanding Scientific Notation

A number represented in scientific notation is written as a number between 1 and 10 multiplied by a power of 10.

The power of 10 is written as a 10 with a raised number by its side. The raised number is called an exponent.

It tells you how many times the 10 is multiplied by itself, or how many 0s there are after the 1.

1.2 × **10 ^{3}** = 1.2 ×

**10 × 10 × 10**= 1.2 ×

**1,000**

So 1.2 × 10^{3} represents the number given by 1.2 × 1000, which is 1,200.

1.2 × 10^{3} = 1,200

## Why Is Scientific Notation Useful?

Scientific notation is useful because it allows us to write very large or very small numbers in a shorter, standard way.

Some examples of numbers written in scientific notation are shown below, along with the numbers written in full. Notice that it can save you writing lots of 0s.

When numbers are very small (less than 1), we can also save writing 0s by using scientific notation. In this case, the power of 10 can has a negative exponent:

## Converting a Number into Scientific Notation

Scientific notation is a useful way to write long numbers.

To convert the number to scientific notation, we have to move the decimal point to the right of the first digit.

Even though it isn't written, the decimal point is at the end of the number. Count how many places it has to move left so it is to the right of the first digit (1):

The decimal point has to be moved **5** places to the left to make **1.23**. The number is written as **1.23 × 10 ^{5}**.

## Converting Scientific Notation to a Number

When you see a number written in scientific notation, you must know what number it represents.

To convert scientific notation to a number, we have to move the decimal point right. The exponent of the power of 10 is **5** so the decimal point needs to be moved **5** places.

You will need to add **0**s so that the decimal point can be moved:

The decimal point has to be moved **5** places to the right to make **123,000**.