Learning how to use a number line when adding and subtracting is a first grade, Common Core math skill: 1.OA.5. Below we show two videos that demonstrate this standard. Then, we provide a breakdown of the specific steps in the videos to help you teach your class.
Your students should be familiar with the Kindergarten skill of understanding the number pairs that equal 10 and knowing all decompositions (e.g. 5=4+1, 5=2+3) of numbers below 10. This skill builds a foundation for strategy development, the understanding of place values, and properties of operations (K.OA.3-4). Your students should also understand that ten 1’s plus more 1’s are considered “teens” (K.NBT.1).
Understanding how to perform addition and subtraction within 20 will enable your students to perform similar skills up to 100, eventually extending those skills to work with larger numbers and solve two-step word problems (2.OA.1). They will also be able to apply this skill with problems in a variety of contexts involving length, picture graphs and bar graphs (2.NBT.5).
Common Core Standard: 1.OA.5 - Relate counting to addition and subtraction
Students who understand this principle can:
2 Videos to Help You Teach Common Core Standard: 1.OA.5
Below we provide and breakdown two videos to help you teach your students this standard.
Video 1: Count to Add and Subtract with Miss D. Gunn
This video is a resource for teachers and parents that provides a brief example of an activity you can do with your students. The activity helps students connect the idea with counting to addition and subtraction.
Here is a list of suggested materials for the activity.
Her first example is an addition problem: 3 + 7 = ?
The second example shows how to use this method with a subtraction problem: 7 - 3 = ?
Video 2: Using a Number Line to Add and Subtract
The video begins by reminding students of the basics of adding and subtracting by helping Jake count his library books.
Jakes likes to borrow books from the library and currently has 4 books. However, he needs more books for a project, and so Jake gets 3 more books. Boddle asks how many books he now has and uses a number line to find out.
The video then goes into a subtraction example. The librarian reminds Jake that he needs to return 2 books. Boddle asks how many books will be left once Jake returns the 2 books and uses a number line.
The video ends by reminding students that, when using a number line, “Addition” means moving to the right, and “Subtraction” means moving to the left.
Want more practice?
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*Information on standards is gathered from The New Mexico Public Education Department's New Mexico Instructional Scope for Mathematics and the Common Core website.