Use knowledge of the distributive law to solve two part problems
I can use knowledge of the distributive law to solve two part addition problems efficiently.
- Year 4
Use knowledge of the distributive law to solve two part problems
I can use knowledge of the distributive law to solve two part addition problems efficiently.
Lesson details
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.
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.
Q5.Which of the following expressions is the array representing?
