Computer Science
Grade 7
20 min
1. Introduction to Binary Numbers
Understand the concept of binary numbers (base-2) and how they differ from decimal numbers (base-10).
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Introduction & Learning Objectives
Learning Objectives
Define the term 'binary' and explain why computers use it.
Identify a 'bit' as the smallest unit of data and a 'byte' as a group of 8 bits.
Explain the concept of a Base-2 number system compared to our Base-10 (decimal) system.
Count from 0 to 10 in binary.
Convert any 4-bit binary number into its decimal equivalent.
Convert any decimal number from 0 to 15 into its 4-bit binary equivalent.
Ever wonder how your computer understands everything from your favorite game to your homework? 🎮 It all starts with just two numbers!
In this lesson, we'll pull back the curtain and learn the secret language of computers: binary! You'll discover how simple 'on' and 'off' signals can represent every piece of i...
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Key Concepts & Vocabulary
TermDefinitionExample
BinaryA number system that uses only two digits, 0 and 1. It is the fundamental language of computers because it represents the 'off' and 'on' states of an electrical switch.The number `1010` is a binary number.
BitShort for 'Binary Digit', it is the smallest unit of data in a computer. A bit can have a value of either 0 or 1.In the binary number `1010`, the first `1` is one bit.
ByteA group of 8 bits. A byte is a common unit of measurement for digital information and is often used to represent a single character, like the letter 'A'.The byte `01000001` represents the capital letter 'A'.
Base-2Another name for the binary system. It's called Base-2 because it only has two digits (0 and 1) to build all its numbers....
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Core Syntax & Patterns
Binary Place Value
... 128 | 64 | 32 | 16 | 8 | 4 | 2 | 1
Each position in a binary number represents a power of 2, starting from 2⁰ (which is 1) on the far right. Each place to the left is the next power of 2 (2¹, 2², 2³, etc.).
Algorithm: Binary to Decimal Conversion
Sum of (digit × place_value) for all digits.
To convert a binary number to decimal, multiply each binary digit (0 or 1) by its corresponding place value and then add all the results together.
Algorithm: Decimal to Binary Conversion
Find the largest power of 2 that fits into the number, place a '1' in that position, subtract it, and repeat with the remainder.
Start with your decimal number. Find the largest place value that is less than or equal to your number. Put a '1' in that posi...
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Challenging
A byte is a group of 8 bits. The place values continue to double (..., 32, 16, 8, 4, 2, 1). What is the decimal value of the 5th bit from the right?
A.8
B.32
C.16
D.5
Challenging
You have the 4-bit binary number `1100` (which is 12 in decimal). If you 'flip' all the bits, changing every 1 to a 0 and every 0 to a 1, what is the new decimal value?
A.2
B.3
C.4
D.1
Challenging
The tutorial shows that the decimal number 12 is made by adding the place values 8 and 4 (`1100`). Which combination of place values would be used to represent the decimal number `14` in binary?
A.8 + 4 + 2 + 1
B.8 + 2 + 1
C.16 + 2
D.8 + 4 + 2
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