Explain the use of placeholders when multiplying whole numbers by 100
Lesson details
Learning outcome
I can use place value to explain placing 2 0's after the final digit when we multiply whole numbers by 100
Key learning points
- Multiples of 100 have zero in the tens and ones column.
- When a number is multiplied by one hundred the product is a multiple of one hundred.
- Multiplying by one hundred moves all the digits two columns to the left making the digits one hundred times the size.
Keywords
Placeholder - A placeholder is where we use the digit 0 to hold a place in a number and maintain place value.
Magnitude - The magnitude of a number is its distance from 0
Common misconception
Many pupils believe that 'adding 2 zeros' is multiplying by 100 which can lead to difficulties later on when they are introduced to decimal numbers.
Don't dismiss it. It's a pattern that has been spotted and generalised. Do encourage the children to work with physical resources that don't involve the numbers themselves so they can understand that it isn't adding zero but changing place value.
Teacher tip
Make mistakes in the place value yourself whilst modelling and get the children to spot this. They will enjoy pointing out your mistakes! It helps them to firm up their error-spotting skills and consolidates their understanding.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.What number is being represented using the Base 10 blocks?
Q2.What number is being represented in the place value chart?
Q3.What number is being represented using the place value counters?
Q4.What number is being represented using the Base 10 blocks?
Q5.What number is being represented in the place value chart?
Q6.What number is being represented using the place value counters?
Assessment exit quiz
6 Questions
Q1.Look at the image. The label below the arrow is missing a number. Complete it. times the size.
Q2.Which of the following equations is represented by the place value counters and the arrow in the image?
Q3.True or false? To multiply a whole number by 100, you just add two zeros.
Q4.Which of the following equations is represented by the place value counters and the arrow in the image?
Q5.What is the equation being represented in the place value chart showing before and after?
Q6.Match the numbers with the numbers that are 100 times the size.
To help you plan your 4 maths lesson on: Explain the use of placeholders when multiplying whole numbers by 100, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 4 maths lesson on: Explain the use of placeholders when multiplying whole numbers by 100, 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 2 maths lessons from the Understand what happens when a number is multiplied or divided by 10 and 100 unit, dive into the full primary maths curriculum, or learn more about lesson planning.