Number bases
Lesson details
Learning outcome
I know the difference between base-2 and base-10 numbers and I can convert between these bases.
Key learning points
- Number systems use place value to represent the value of each digit in a number.
- The base of a number system refers to the range of values a digit can take.
- Decimal is a base-10 number system.
- Binary is a base-2 number system.
Keywords
Place value - a digit's value based on its position in a number
Base-10 - number system using digits 0-9, where each place value is a power of ten
Base-2 - number system using only the digits 0 and 1, where each place value is a power of two
Decimal - a base-10 number system that uses the digits 0 to 9
Common misconception
Pupils may think the place value for binary is the same as decimal in the fact each place value to the left is 10 times greater.
Binary place values double. So the first bit has the place value of 1 and the second has the place value of 2 and so on.
Teacher tip
Encourage pupils to use the conversion tables when converting between binary and decimal and vice versa. Even though they can be done without, pupils make mistakes with visualising the place value order.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What does the term 'data' mean in computing?
Q2.What is a transistor?
Q3.In a binary system, if on is represented by 1, what represents off?
Q4.Why do computers use binary to represent data?
Q5.What is the highest-value digit in binary?
Q6.Match the words to their correct description.
raw facts, such as numbers or text, presented without any meaning
a number system that uses the digits 0 and 1 to represent data
directions on how to carry out a specific task
a tiny electronic switch controlled by electricity
Assessment exit quiz
6 Questions
Q1.What is the base of the binary number system?
Q2.What is a digit’s value based on its position in a number known as?
Q3.What digits are used in decimal numbers?
Q4.What is the decimal value of the binary number 1101?
Q5.What is the binary representation of the decimal number 10?
Q6.Match the term to the correct description.
128, 64, 32, 16, 8, 4, 2, 1
10000, 1000, 100, 10, 1
a number system with 0 to 9, where each place value is a power of ten
a number system with 0 and 1, where each place value is a power of two
a base-10 number system
To help you plan your 10 computer science lesson on: Number bases, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 computer science lesson on: Number bases, download all teaching resources for free and adapt to suit your pupils' needs.
The starter quiz will activate and check your pupils' prior knowledge, with versions available both with and without answers in PDF format.
We use learning cycles to break down learning into key concepts or ideas linked to the learning outcome. Each learning cycle features explanations with checks for understanding and practice tasks with feedback. All of this is found in our slide decks, ready for you to download and edit. The practice tasks are also available as printable worksheets and some lessons have additional materials with extra material you might need for teaching the lesson.
The assessment exit quiz will test your pupils' understanding of the key learning points.
Our video is a tool for planning, showing how other teachers might teach the lesson, offering helpful tips, modelled explanations and inspiration for your own delivery in the classroom. Plus, you can set it as homework or revision for pupils and keep their learning on track by sharing an online pupil version of this lesson.
Explore more key stage 4 computer science lessons from the Representation of numbers unit, dive into the full secondary computer science curriculum, or learn more about lesson planning.