As part of this course you will be required to convert binary number to and from denary, our base 10 number system.

We’ve already seen that binary uses powers of 2 to convert from Denary (base 10) to Binary (base 2), and using the conversion table below is a useful way to help you to convert as you will not have a calculator in your exam:

128Â 64Â 32Â 16Â 8Â 4Â 2Â 1

Â 0Â Â 0Â Â 1Â Â 0Â Â 1Â 0Â 1Â 0

In

the table above, weâ€™ve converted the number 42 into binary by placing

the powers of 2 in different columns and placing a 1 under the numbers

that you would use to add up to 42. So in this case: 32 + 8 + 2 = 42

We can use this process in reverse to convert a binary number back into denary by writing the powers of 2 over each digit and adding up the columns with a 1 in. If your binary number is longer than 8 digits (bits) just keep doubling the numbers in the columns!

## Task

Once you have completed the video lesson at the top of the page, try the practice questions below:

If you would prefer to download the questions as a printable practice sheet, download the worksheet in the “Exercises” tab.