Objective: Students will build simple arrays and equal groups to build a conceptual understanding of multiplication.
Vocabulary: multiplication, array, equal group
Warm up Questions:
- How are addition and multiplication alike?
- How are addition and multiplication different?
Multiplication is adding groups that are the same size.
There are 3 groups of 2 candies.
You can add: 2 + 2 + 2 = 6
You can multiply 3 groups of 2 : 3 x 2 = 6
You can add 2 + 1 cupcakes.
You cannot multiply a group of 2 and a group of 1.
Why can’t you multiply a group of 2 and a group of 1?
Multiplication is a faster way to add equal groups.
The groups must be equal!
2 x 1 can mean..
Multiplication can also be shown with an array.
These are both arrays.
What do the arrays represent? Select all that apply
This array has 4 rows. There are 2 squares in each row.
We can find the total by adding 2 + 2 + 2 + 2 = 8.
Since the groups are all the same size, we can also multiply 4 groups of 2.
It looks like this: 4 x 2 = 8.
Math Error Analysis
What’s the mistake?
These groups are not equal! They can be added but not multiplied.
2 + 5 = 7
2 x 5 does equal 10 but it does not match the model.
Closing Question
- Would it be faster to add 6 seven times or multiply 6 x 7 once?
Resources to Introduce Multiplication
The lesson from this blog post is part of our 3rd Grade Math Curriculum. Want more lessons like this one? Click here to view the editable mini-lessons.
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