Convert 20 from decimal to binary (base 2) notation:

Start by raising our base of 2 to a power starting at 0 and increasing by 1 until it is >= 20

2

2

2

2

2

2

Since 32 is greater than 20, we use 1 power less as our starting point which equals 4.

Now start building our binary notation working backwards from a power of 4.

We start with a total sum of 0:

2

The highest coefficient less than 1 we can multiply this by to stay under 20 is 1.

Multiplying this coefficient by our original value, we get: 1 * 16 = 16.

Adding our new value to our running total, we get: 0 + 16 = 16.

This is <= 20, so we assign our outside coefficient of 1 for this digit.

Our new sum becomes 16.

Our binary notation is now equal to 1

2

The highest coefficient less than 1 we can multiply this by to stay under 20 is 1.

Multiplying this coefficient by our original value, we get: 1 * 8 = 8.

Adding our new value to our running total, we get: 16 + 8 = 24.

This is > 20, so we assign a 0 for this digit.

Our total sum remains the same at 16.

Our binary notation is now equal to 10

2

The highest coefficient less than 1 we can multiply this by to stay under 20 is 1.

Multiplying this coefficient by our original value, we get: 1 * 4 = 4.

Adding our new value to our running total, we get: 16 + 4 = 20.

This = 20, so we assign our outside coefficient of 1 for this digit.

Our new sum becomes 20.

Our binary notation is now equal to 101

2

The highest coefficient less than 1 we can multiply this by to stay under 20 is 1.

Multiplying this coefficient by our original value, we get: 1 * 2 = 2.

Adding our new value to our running total, we get: 20 + 2 = 22.

This is > 20, so we assign a 0 for this digit.

Our total sum remains the same at 20.

Our binary notation is now equal to 1010

2

The highest coefficient less than 1 we can multiply this by to stay under 20 is 1.

Multiplying this coefficient by our original value, we get: 1 * 1 = 1.

Adding our new value to our running total, we get: 20 + 1 = 21.

This is > 20, so we assign a 0 for this digit.

Our total sum remains the same at 20.

Our binary notation is now equal to 10100

We are done. 20 converted from decimal to binary notation equals