Binary shifts
Lesson details
Learning outcome
I can perform binary shifts to multiply and divide binary numbers, but recognise the errors this may introduce.
Key learning points
- Binary shifting is shifting the bits to the left or to the right.
- If you shift to the left, you multiply the number by a power of 2.
- If you shift to the right, you divide the number by a power of 2.
- Overflow is when a number is too large to be stored in allocated memory.
- Underflow is when a number is too small to be processed.
Keywords
Binary shifting - when binary digits are moved left or right, multiplying or dividing them by powers of 2
Overflow - when a number is too large to be represented in the available binary digits
Underflow - when a number is too small to be represented in the available binary digits
Common misconception
When performing binary multiplication any result can be stored, regardless of how many binary digits are needed.
The size of a binary number that can be stored is allocated in memory. Sometimes the result of a binary shift may result in a larger binary number that can be stored in the number of bits available.
Teacher tip
Computers are not infalable and can make mistakes. Based on the example in the slide deck, discuss with pupils other things that might go wrong with computers when the data they used is limited.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Match the terms to the description.
a number system using 0 and 1
a number system using the digits 0 to 9
a switch in an electronic circuit
a direction for performing a task
Q2.What number system uses only the digits 0 and 1?
Q3.What is the base of the decimal number system?
Q4.What is a carry in binary addition?
Q5.What is the result of the binary addition 1 + 1?
Q6.What is the result of the binary addition 11001 + 111?
Assessment exit quiz
6 Questions
Q1.Match the terms with their descriptions
multiplies by powers of 2
divides by powers of 2
when memory capacity is exceeded
when digits are rounded down as they drop near zero
Q2.What is an overflow in binary operations?
Q3.Which of the following can cause overflow?
Q4.In binary, what is 11001 × 10?
Q5.In binary, what is 11001 ÷ 100?
Q6.What should be considered when storing binary multiplication results?
To help you plan your 10 computer science lesson on: Binary shifts, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 10 computer science lesson on: Binary shifts, 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.