Question Video: Using a Number Line to Add within 100, Including a Two-Digit Number and a One-Digit Number

Video Transcript

Use the number line to find the sum of 49 and nine.

We have to use the number line to add 49 plus nine. So we need to start at 49 and count forward on the number line nine more. One ⁠— 49 and one more makes 50. We could add one and then eight more because nine is one and eight. 49 and one is 50. Now we need to add eight more. One, two, three, four, five, six, seven, eight. 50 and eight more is 58. To add nine to 49, we added one to take us to 50. And then we added eight more to take us to 58. 49 plus nine equals 58.⁠