Learning how to add and subtract within 1000 using different techniques is a second grade, Common Core math skill: 2.NBT.7. 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 first grade skill of counting up to 120 starting from any number below 120 (1.NBT.1), this skill helps them understand greater or less than values. The second grade skill is also closely linked to the first grade skill of understanding place values (ones and tens) in two-digit numbers (1.NBT.2).
Comparing large numbers as greater than, less than, and equal to will help your students understand future concepts in third grade. In third grade, your students will learn how to interpret the products of whole numbers (i.e. 8 x 3 is the same as 8 groups of 3 objects each) (3.OA.1). They will also learn to use multiplication and division within 100 while solving word problems in situations that involve “equal groups, arrays, and measurement quantities” (3.OA.3).
Common Core Standard: 2.NBT.7 - Add and subtract within 1000, using concrete models, drawings, and strategies based on place value, properties of operations, and/or the relationship between addition and subtraction
Students who understand this principle can:
2 Videos to Help You Teach Common Core Standard: 2.NBT.7
Below we provide and breakdown two videos to help you teach your students this standard.
Video 1: Hop Along with Cricket on an Open Number Line
The video begins by asking students, “How do you add 514 + 253 using an open number line?” In this lesson, students will learn to add within 1000 using an open number line.
Before moving into the core lesson, the video provides a brief review of some math facts pertinent to the lesson.
After, the video moves straight into the core lesson: “Add 243 + 437” using an open number line.
Your students just completed 243 hops in 3 easy steps, finding the answer: 243 + 437 = 680.
The video explains a common misunderstanding is that you can only hop based on place value from hundreds down to ones, but hopping up in a different order works too. The video shows this is true using the above problem, hopping up first by 3, then 100, then 100 more, and then 40, landing on 680.
Next, the video offers another problem: Solve 351 + ___ = 738.
Usually we start with the biggest addend, but in this case, there’s only one. So, we start with that and hop up the number line until we get to 738, which we can write at the end of the number line.
The video closes by reminding students what they have learned.
Video 2: Sending Letters and Solving Problems
This video covers adding and subtracting within 1000. First, for practice, Boddle helps some postmen send some mail.
Each mailbox has an addition or subtraction problem, and the answers are written on the envelopes. To put the correct letter in the mailbox, we simply have to match the envelope to the right mailbox.
Boddle recaps what we have learned in this lesson:
Hope this helps! See you next time!
Want more practice?
Give your students additional standards-aligned practice with Boddle Learning. Boddle includes questions related to Comparing and Measuring Lengths plus rewarding coins and games for your students to keep them engaged. Click here to sign up for Boddle Learning and create your first assignment today.
*Information on standards is gathered from The New Mexico Public Education Department's New Mexico Instructional Scope for Mathematics and the Common Core website.