Computer Science
Grade 3
20 min
Binary Review: Recap and Reflection
Students will review the concepts learned in the previous lessons and reflect on their understanding of binary.
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Introduction & Learning Objectives
Learning Objectives
Recall that computers use a special language called binary made of only 0s and 1s.
Explain that a 'bit' is a single binary digit, either a 0 or a 1.
Identify the 'on' (1) and 'off' (0) states of a bit using the light switch analogy.
Convert numbers from 0 to 7 into 3-bit binary code.
Convert 3-bit binary codes back into regular numbers (0-7).
Arrange binary cards (with dots) to represent a given number.
Reflect on why a simple two-symbol system is useful for computers.
Have you ever wanted to speak a secret computer language? 🤫 Let's review the super simple language of 0s and 1s that powers all our favorite games and apps!
Today, we're going to do a recap of binary, the special code computers use. We will rememb...
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Key Concepts & Vocabulary
TermDefinitionExample
BinaryA special language that computers use. It only has two symbols: 0 and 1.The number 2 in binary is written as '10'.
BitA single binary digit. It is the smallest piece of information a computer can store. It can only be a 0 or a 1.In the binary number '101', there are three bits: 1, 0, and 1.
OnThe state represented by the number 1. It's like a light switch that is flipped on.If a bit is '1', it means that part of the computer's memory is 'on'.
OffThe state represented by the number 0. It's like a light switch that is flipped off.If a bit is '0', it means that part of the computer's memory is 'off'.
Place ValueThe value of a digit based on its position in a number. In binary, the plac...
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Core Syntax & Patterns
The On/Off Rule
1 = On, 0 = Off
This is the most important rule. Think of a light bulb. If a bit is 1, its light is on. If the bit is 0, its light is off.
The Place Value Pattern (Right to Left)
..., 8, 4, 2, 1
To find the value of a binary number, you must know the value of each spot. Always start with 1 on the far right, and then double the value for each spot as you move to the left.
The Adding Rule
Add the values of the 'On' places.
To read a binary number, you only add up the place values that have a 1 (are 'On'). You ignore the places that have a 0.
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Challenging
Imagine a new number system called 'Trinary' that uses the digits 0, 1, and 2. If our normal system is 'base-10' and binary is 'base-2', what would 'Trinary' be called?
A.Base-3
B.Base-1
C.Base-T
D.Base-012
Challenging
A simple robot can only understand 2-bit commands (like 00, 01, 10, 11). This gives it 4 possible commands. If you wanted to give it 8 possible commands, how many bits would you need for each command?
A.2 bits
B.3 bits
C.4 bits
D.8 bits
Challenging
A friend says, 'Using binary, I can represent any whole number, no matter how big!' What is the best reflection on this statement?
A.False, because you can only make small numbers with 0 and 1.
B.False, because you can't write odd numbers in binary.
C.True, but you might need to add more bits for bigger numbers.
D.True, but only if you are also allowed to use the number 2.
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