Add to a Two-Digit Number Using a Number Line Video

Ryder and Holly’s grandparents are visiting from out of town. They are all on a walk, counting the jack-o’-lanterns they see at different houses. Let’s help them count the jack-o’-lanterns!

Here is the first house. There are so many jack-o’-lanterns! Let’s count the happy ones first. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12. There are 12 happy jack-o’-lanterns. Now let’s count the sad ones.

1, 2, 3, 4, 5. There are 5 sad jack-o’-lanterns.

We can help Ryder and Holly add 12 and 5 together by using the counting on strategy with a number line. Number lines help us see and understand the numbers we add. Let’s start by

circling 12 on the number line because it’s the largest addend. Now count on by jumping to the right 5 times. This shows 12 + 5. We landed on the number 17. That means 12+5=17. Great job!

Let’s look at the next house. How many happy jack-o’-lanterns do you see? That’s right! There are 37. How many sad jack-o’-lanterns do you see?

Yes, there are 8 sad jack-o’-lanterns.

Let’s find the total amount of jack-o’-lanterns by using the number line again. Our addition sen- tence is 37+8. Remember, we always begin by finding the largest addend on the number line.

Here is 37. Now let’s count on by jumping to the right 8 times to show “plus 8”. Good! What number did we land on?

That’s right! We landed on 45. This house has 45 jack-o’-lanterns.

There are 16 happy jack-o’-lanterns at this house. How many sad ones do you see? That’s right! There are 15 sad jack-o’-lanterns.

Can you help Ryder and Holly add 16 and 15 together? Our addition sentence is 16+15. Begin by finding the largest addend on the number line.

Very good! Here is 16. How many jumps will you make?

Good! You need to jump to the right 15 times to complete 16+15. The number line shows us that 16+15=31.

Here is the last house on Ryder and Holly’s walk with their grandparents. We can see that there are 14 happy jack-o’-lanterns and 7 sad jack-o’-lanterns.

What is our addition sentence?

Yes! 14+7. 14 is the larger addend, so we can begin counting on from 14. Make 7 jumps to the right. Very good! 14+7=21.

These houses are decorated and ready for the night! Thank you for helping Ryder, Holly, and their grandparents use the number line to add. Now they know exactly how many happy and sad jack-o’-lanterns there are at each house. Great job!