Use knowledge of the distributive law to solve two part problems
Lesson details
Learning outcome
I can use knowledge of the distributive law to solve two part addition problems efficiently.
Key learning points
- Partitioning a factor is called distribution or using the distributive law.
- Factors can be re-combined to simplify 2-part addition problems.
- Five 9s plus three 9s is equal to eight 9s.
Keywords
Common factors - When we compare lists of factors of two or more numbers, any factors that are the same are the common factors.
Distributive law - The distributive law says that multiplying a number by a group of numbers added together is the same as doing each multiplication separately.
Common misconception
When looking at an expression such as 9 × 3 + 9 × 6 children might be tempted to add first leading to an expression like this: 9 × 12 × 6
Ensure that you support the equation with the arrays so that pupils understand where the multiplication expressions come from and they can match the partial products to the arrays.
Teacher tip
Worded problems are used to contextualise. Consider your class and adapt contexts if needed to suit.
Licence
Lesson video
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Prior knowledge starter quiz
6 Questions
Q1.Which of the numbers in the following equation are the factors? 21 = 7 × 3
Q2.54 + 8 =
Q3.62 + 25 =
Q4.There are 4 bags of 5 apples. Match the object with group size or number of groups.
number of groups
group size
Q5.Which of the following expressions is the array representing?
Q6.Double 56 is ___
Assessment exit quiz
6 Questions
Q1.Tick the expressions that are equal in value to 3 × 8
Q2.Tick the expressions that are equal in value to 5 × 9
Q3.Which number goes in both gaps as a common factor? 2 × + ___ × 3 = 20
Q4.Use distributive law to solve the two part addition of 2 × 4 + 2 × 5 =
Q5.Use distributive law to solve the two part addition of 3 × 8 + 8 × 5 =
Q6.Use distributive law to solve the two part addition of 9 × 3 + 5 × 9 =
To help you plan your 4 maths lesson on: Use knowledge of the distributive law to solve two part problems, download all teaching resources for free and adapt to suit your pupils' needs...
To help you plan your 4 maths lesson on: Use knowledge of the distributive law to solve two part problems, 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 Apply the distributive law to multiplication unit, dive into the full primary maths curriculum, or learn more about lesson planning.