Video: Adding Three Numbers Whose Sum is within 20 by First Making Ten

Answer the questions to find an easy way to add 6 + 7 + 3. What is 7 + 3? What is 6 + 10? What is 6 + 7 + 3?

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Video Transcript

Answer the questions to find an easy way to add six plus seven plus three. The questions are what is seven plus three? What is six plus 10? And then what is six plus seven plus three?

We know that if we add any numbers together, we can add them in whatever order we like. And it will always make the same total. So when we get presented with three numbers to add together, we can look carefully at them and think, which one should we start by adding first? Because these are small numbers, we can ask ourselves, can I see a pair that I can put together to make 10 quickly?

And that’s why we’re starting with seven plus three. What is seven plus three? The total of seven and three is 10. Because we know the total of seven and three, all we need to do now is add this to the first number. And that’s why our second question asks us, what is six plus 10? Six plus 10 equals 16.

And so our final question puts the two steps together. What is six plus seven plus three? First, we have the two numbers that we can do quickly in our heads. Seven plus three equals 10. Then we add this to the first number. Six plus 10 equals 16. Six plus seven plus three equals 16.

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