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In this lesson, we will learn how to apply the associative property of addition of three numbers whose sum is, at most, 20.
Q1:
Rania has 20 counters.
Use the counters to find the missing number.
Q2:
Find the missing number in 1 6 + 3 + 1 = + 1 .
Using that 1 6 + 3 + 1 = 1 9 + 1 , what is 1 6 + 3 + 1 ?
Q3:
Maged had 5 chocolate bars, 4 lollipops, and 3 gummy bears.
In total, he had candies.
Find another way to write the total number of candies.
Q4:
Find the missing number in 1 3 + 4 + 7 = + 7 .
Q5:
We will see how we can write 4 + 6 + 3 in different ways.
Find the missing number.
Complete the missing sum.
All of these sums are equal. What are they equal to?
Q6:
When we add three numbers, we can first add any two of them.
For example, to find 8 + 6 + 7 , we could first add 8 and 6 to get 14 as the picture shows.
Now, can you find the missing number?
Q7:
Q8:
Am I using the equal sign correctly? Check if the two sums are equal.
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