Menu

Math Lesson 1.7.3 - Other Number Systems - The Base 2 Number System

Please provide a rating, it takes seconds and helps us to keep this resource free for all to use

[ 1 Votes ]

Welcome to our Math lesson on Other Number Systems - The Base 2 Number System, this is the third lesson of our suite of math lessons covering the topic of Decimal Number System and Other Numbering Systems, you can find links to the other lessons within this tutorial and access additional Math learning resources below this lesson.

Other Number Systems - The Base 2 Number System

As stated earlier, we use a base 10 number system (hence the name decimal), where we use 10 different digits to write all numbers. However, the decimal system is not the only number system used in practice. For example, computers use the base 2 number system to operate. This is done only for convenience, as it is much easier for the machine to handle two types of input signals rather than ten different ones. Hence, computers are built in such a way that they recognize only two types of input voltages: 0 volt (this means zero input or no input) or 5 volt (this means maximum input). The computer then converts the 0 volt input in a number form (the 0 volt input appears on the screen as the digit 0) and the 5 volt input is shown on the screen by the digit 1. Hence, when you see a number on a computer screen like this

00010010

It is important to understand that there are 8 consecutive inputs on the computer produced by the power source that are interpreted as

no signal - no signal - no signal - signal - no signal - no signal - signal - no signal

However, this is not the point we want to discuss, as we are here to explain how this base 2 system (also known as binary system) is related to the base 10 system we use our everyday routine. Hence, we can say that basically, the logic of base 2 number system is similar to base 10 number system. The value of digits increases from right to left, just in the decimal system; the only difference is that in the base 2 number system we use only the digits 0 and 1 to write all numbers instead of 0, 1, 2, 3, 4, 5, 6, 7, 8 and 9 that we use to write numbers in the decimal system. In this way, a binary number does not have ones, tens, hundreds, thousands etc., but ones, twos, fours, eights, and so on.

In addition, a binary number can be decomposed in powers, but this time in powers of 2 instead of in powers of 10 as occurs in decimal numbers. Thus, if we read the number

10110101

we can decompose it as 1 × 27 + 0 × 26 + 1 × 25 + 1 × 24 + 0 × 23 + 1 × 22 + 0 × 21 + 1 × 20.

We can find which number in the decimal system the above binary number does correspond. Thus, doing the operations, we obtain

10110101 = 1 × 27 + 0 × 26 + 1 × 25 + 1 × 24 + 0 × 23 + 1 × 22 + 0 × 21 + 1 × 20
= 1 × 128 + 0 × 64 + 1 × 32 + 1 × 16 + 0 × 8 + 1 × 4 + 0 × 2 + 1 × 1
= 128 + 32 + 16 + 4 + 1
= 181

Example 4

What number in the decimal system does the number 1001001 correspond?

Solution 4

We have

1001001 = 1 × 26 + 0 × 25 + 0 × 24 + 1 × 23 + 0 × 22 + 0 × 21 + 1 × 20
= 1 × 64 + 0 × 32 + 0 × 16 + 1 × 8 + 0 × 4 + 0 × 2 + 1 × 1
= 64 + 8 + 1
= 73

We can also convert a decimal number into a binary one by dividing it recurrently by 2 and then taking all remainders of division from the last to the first to write the corresponding binary number. Let's consider an example to clarify this point.

Example 5

Write the binary form of the base 10 number 157.

Solution 5

We have:

157 ÷ 2 = 78 (1)
78 ÷ 2 = 39 (0)
39 ÷ 2 = 19 (1)
19 ÷ 2 = 9 (1)
9 ÷ 2 = 4 (1)
4 ÷ 2 = 2 (0)
2 ÷ 2 = 1 (0)
1 ÷ 2 = 0 (1)

Thus, taking the remainders from the last to the first, we obtain

(157)10 = (10011101)2

Proof::

1 × 27 + 0 × 26 + 0 × 25 + 1 × 24 + 1 × 23 + 1 × 22 + 0 × 21 + 1 × 20
= 1 × 128 + 0 × 64 + 0 × 32 + 1 × 16 + 1 × 8 + 1 × 4 + 0 × 2 + 1 × 1
= 128 + 16 + 8 + 4 + 1
= 157

Hence, the solution was correct.

More Decimal Number System and Other Numbering Systems Lessons and Learning Resources

Arithmetic Learning Material
Tutorial IDMath Tutorial TitleTutorialVideo
Tutorial
Revision
Notes
Revision
Questions
1.7Decimal Number System and Other Numbering Systems
Lesson IDMath Lesson TitleLessonVideo
Lesson
1.7.1The Meaning of Decimal Number System. Writing a Number in Terms of Powers of Ten
1.7.2Place Values and Classes
1.7.3Other Number Systems - The Base 2 Number System
1.7.4Operations with Binary Numbers
1.7.5The Base 16 Number System

Whats next?

Enjoy the "Other Number Systems - The Base 2 Number System" math lesson? People who liked the "Decimal Number System and Other Numbering Systems lesson found the following resources useful:

  1. Base Two Feedback. Helps other - Leave a rating for this base two (see below)
  2. Arithmetic Math tutorial: Decimal Number System and Other Numbering Systems. Read the Decimal Number System and Other Numbering Systems math tutorial and build your math knowledge of Arithmetic
  3. Arithmetic Video tutorial: Decimal Number System and Other Numbering Systems. Watch or listen to the Decimal Number System and Other Numbering Systems video tutorial, a useful way to help you revise when travelling to and from school/college
  4. Arithmetic Revision Notes: Decimal Number System and Other Numbering Systems. Print the notes so you can revise the key points covered in the math tutorial for Decimal Number System and Other Numbering Systems
  5. Arithmetic Practice Questions: Decimal Number System and Other Numbering Systems. Test and improve your knowledge of Decimal Number System and Other Numbering Systems with example questins and answers
  6. Check your calculations for Arithmetic questions with our excellent Arithmetic calculators which contain full equations and calculations clearly displayed line by line. See the Arithmetic Calculators by iCalculator™ below.
  7. Continuing learning arithmetic - read our next math tutorial: Numbering Systems, a Historical View

Help others Learning Math just like you

Please provide a rating, it takes seconds and helps us to keep this resource free for all to use

[ 1 Votes ]

We hope you found this Math tutorial "Decimal Number System and Other Numbering Systems" useful. If you did it would be great if you could spare the time to rate this math tutorial (simply click on the number of stars that match your assessment of this math learning aide) and/or share on social media, this helps us identify popular tutorials and calculators and expand our free learning resources to support our users around the world have free access to expand their knowledge of math and other disciplines.

Arithmetic Calculators by iCalculator™