In these lessons we shall learn the binary number system and how to convert between binary and decimal numbers.
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Number System
In a binary number (or base two) system, we use only two digits: 0 and 1.
The following diagrams show the place values for binary numbers and how to convert from binary to decimal.

Like base ten numbers, we can determine the value of a base two number by placing each digit in its respective place value, then writing its expanded notation.
Example:
Find the value of each of the following binary numbers, giving the values in decimal numbers:
a) 1012
b) 10112
c) 101012
Solution:
a)
| 24 | 23 | 22 | 21 | 20 |
| 1 | 0 | 1 |
b)
| 24 | 23 | 22 | 21 | 20 |
| 1 | 0 | 1 | 1 |
c)
| 24 | 23 | 22 | 21 | 20 |
| 1 | 0 | 1 | 0 | 1 |
How To Convert Binary To Decimal?
We can convert a decimal number into a binary number by repeatedly dividing the base ten number by two. Then, write the remainders from the bottom to the top as the answer:
Example:
Write each of the following base ten numbers as a binary number:
a) 510
b) 7810
Solution:
a)

510 = 1012
b)

7810 = 10011102
Base 10 to Base 2 (Decimal to Binary) Conversion
A demonstration of the repeated divide by 2 method for converting numbers from base 10 (or decimal)
into base 2 (or binary) form.
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