New
New
Year 4

Use knowledge of the distributive law to solve problems in different contexts

I can use knowledge of the distributive law to solve problems in different contexts efficiently.

New
New
Year 4

Use knowledge of the distributive law to solve problems in different contexts

I can use knowledge of the distributive law to solve problems in different contexts efficiently.

Lesson details

Key learning points

  1. The distributive law allows you to add or subtract known times tables to solve problems.
  2. You can partition the group number or the size of a group to solve problems.
  3. Factors can be re-combined or subtracted to simplify 2-part problems.

Common misconception

Pupils may be less familiar with the names and properties of polygons and this may be a distraction from the focus of the learning.

Consider providing scaffolds for some pupils or pre-learning to revise shape names and properties.

Keywords

  • 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.

  • Polygon - A polygon is a 2D shape made up of 3 or more straight lines.

Race off the counting method compared to using the distributive law to find the number of sides of a group of polygons. Hopefully, this will show that the distributive law is quicker and so more efficient.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

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6 Questions

Q1.
Which factor has been partitioned using the distributive law in the second expression here? 5 × 16 = 5 × 8 + 5 × 8
5
Correct answer: 16
8
Q2.
92 + 60 =
Correct Answer: 152
Q3.
64 + 73 =
Correct Answer: 137
Q4.
Which of the following expressions represents the total number of doughnuts if I have 10 boxes of 5 chocolate doughnuts and 3 boxes of 5 strawberry doughnuts.
Correct answer: 10 × 5 + 3 × 5
10 × 3 + 5 × 5
10 + 5 + 3 + 5
10 + 3 + 5 + 5
Q5.
Which of the following expressions is the array representing?
An image in a quiz
7 × 9 + 7 × 5
Correct answer: 2 × 9 + 5 × 9
2 × 7 + 2 × 5
Q6.
Double 78 is
Correct Answer: 156

6 Questions

Q1.
Which of the following expressions is equivalent to 19 × 7?
10 × 9 + 10 × 7
Correct answer: 20 × 7 − 7
20 × 7 − 7 × 19
Q2.
What is the missing number in the array shown?
An image in a quiz
Correct Answer: 8, eight
Q3.
Use the distributive law to calculate how many sides there are in 16 septagons.
An image in a quiz
Correct Answer: 112
Q4.
Use the distributive law to calculate how many sides there are in 19 hexagons.
Correct Answer: 114
Q5.
Andeep has 150 points to spend on battle robots. He wants to buy 8 Chuck robots, which are 19 points each. Can he afford it?
Yes
Correct answer: No
Q6.
Izzy has 120 points to spend on battle robots. She wants to buy 8 Ice robots which are 15 points each. Can she afford it?
Correct answer: Yes
No