# Binary Numbers

## Starter

### Clues

```Across
1. Binary can be used to store text, sound, instructions and _________.
4. On a cd this area is counted as a zero valuable.
5. Binary data is easy and ________ to read.
8. Eight binary digits
9. CD Drives use a _______ to read cds.
10. A number system consisting of just two states
Down
2. The code system used by shipping and telegraphs.
3. Four binary digits
6. One single binary digit
7. The input ________ to a computer system is not very stable.

## Decimal to Binary

### Decimal to Binary Conversion

Let’s suppose we are trying to find the binary for the decimal number 75.

Step 1

### Step 1 – Write the 128 to 1 numbers

Starting on the right hand side, write down the numbers 1, 2,4,8 etc, doubling each time until you reach 128.

Remember smallest number at the right hand side!!!

Step 2

### Step 2 – Cross out the unused numbers

Keeping only the numbers that you need to add up to your decimal number, cross out all other numbers.

Step 3

### Step 3 – Write the ones or zeros

Under each number write a 1 if there is a number and a zero if you crossed out the number. Put the numbers all together and you have your binary number!

## Binary to Decimal

Binary to decimal Conversion

Let’s suppose we are trying to find the decimal for the binary number 01101011.

Step 1

### Step 1 – Write the 128 to 1 numbers

Starting on the right hand side, write down the numbers 1, 2,4,8 etc, doubling each time until you reach 128.

Remember smallest number at the right hand side!!!

Step 2

Step 3

## Practice

Decimal to Binary

Try converting these decimal numbers to binary!

a. 45

b. 12

c. 111

d. 255

e. 0

Binary to Decimal

Try converting these binary numbers to decimal

f. 11101101

g. 00010010

h. 10101010

i. 00101100

j. 10111010

## Activity

Log on to Google Classroom and fill out your learning log for the lesson!

## Class Plenary

Kahoot

Have a go at this plenary as a class

## Resources

### Worksheet Generator

You can use this online worksheet generator to create more worksheets to practice converting from Denary to Binary and back again!0478/12 – Paper 1 Theory May/June 2018 Qn3 Binary Coded Decimal

Past Paper Exam Questions