Convert 21 from decimal to binary (base 2) notation:
Power Test
Raise our base of 2 to a power Start at 0 and increasing by 1 until it is >= 21 20 = 1 21 = 2 22 = 4 23 = 8 24 = 16 25 = 32 <--- Stop: This is greater than 21
Since 32 is greater than 21, we use 1 power less as our starting point which equals 4
Build binary notation
Work backwards from a power of 4 We start with a total sum of 0:
24 = 16
The highest coefficient less than 1 we can multiply this by to stay under 21 is 1 Multiplying this coefficient by our original value, we get: 1 * 16 = 16 Add our new value to our running total, we get: 0 + 16 = 16
This is <= 21, so we assign our outside coefficient of 1 for this digit. Our new sum becomes 16 Our binary notation is now equal to 1
23 = 8
The highest coefficient less than 1 we can multiply this by to stay under 21 is 1 Multiplying this coefficient by our original value, we get: 1 * 8 = 8 Add our new value to our running total, we get: 16 + 8 = 24
This is > 21, so we assign a 0 for this digit. Our total sum remains the same at 16 Our binary notation is now equal to 10
22 = 4
The highest coefficient less than 1 we can multiply this by to stay under 21 is 1 Multiplying this coefficient by our original value, we get: 1 * 4 = 4 Add our new value to our running total, we get: 16 + 4 = 20
This is <= 21, so we assign our outside coefficient of 1 for this digit. Our new sum becomes 20 Our binary notation is now equal to 101
21 = 2
The highest coefficient less than 1 we can multiply this by to stay under 21 is 1 Multiplying this coefficient by our original value, we get: 1 * 2 = 2 Add our new value to our running total, we get: 20 + 2 = 22
This is > 21, so we assign a 0 for this digit. Our total sum remains the same at 20 Our binary notation is now equal to 1010
20 = 1
The highest coefficient less than 1 we can multiply this by to stay under 21 is 1 Multiplying this coefficient by our original value, we get: 1 * 1 = 1 Add our new value to our running total, we get: 20 + 1 = 21
This = 21, so we assign our outside coefficient of 1 for this digit. Our new sum becomes 21 Our binary notation is now equal to 10101
Final Answer
We are done. 21 converted from decimal to binary notation equals 101012.
What is the Answer?
We are done. 21 converted from decimal to binary notation equals 101012.
How does the Base Change Conversions Calculator work?
Free Base Change Conversions Calculator - Converts a positive integer to Binary-Octal-Hexadecimal Notation or Binary-Octal-Hexadecimal Notation to a positive integer. Also converts any positive integer in base 10 to another positive integer base (Change Base Rule or Base Change Rule or Base Conversion) This calculator has 3 inputs.
What 3 formulas are used for the Base Change Conversions Calculator?
Binary = Base 2 Octal = Base 8 Hexadecimal = Base 16