# Video: Addition within 100 Using Number Lines

In this video, we will learn how to use a number line to add one- or two-digit numbers to two-digit numbers by counting on.

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### Video Transcript

Addition within 100 using a number line.

In this video, we’ll learn how to add two numbers within 100 using a number line. When we count forward on a number line, the numbers are increasing. Counting forward is the same as adding. We can use some examples to help show us how to add on a number line.

In this example, we need to use the number line to find the sum of 63 and seven. So we need to start counting at number 63. And then we need to count forward seven because we’re adding seven. Add one, two, three, four, five, six, seven. 63 add seven is 70. We started at 63 on the number line and we counted forward seven.

In this example, we need to use a number line to find the sum of 49 and nine. We need to start counting at number 49 and count forward nine more spaces. We started at 49, counted forward nine spaces. And we finished at number 58. So we can say that 49 plus nine is 58.

In this video, we’ve learned how to add two numbers by counting forward on a number line.