2-Digit Addition
When it comes to 2-Digit Addition Strategies, we want students to understand the numbers, we don’t want them just following rote rules. We want students to find the strategy that makes sense to them and then use it. However, teaching students 2-digit addition strategies can be a challenge and you may not know where to begin. Or you may be looking for some helpful tips in teaching them. Well, keep reading! Because in this blog post I will be sharing all of the 2-digit addition strategies and how to teach them.
Hundreds Chart
Students should have really mastered how a hundreds chart works in 1st grade. They should know you add by tens by going down on the chart. They should know they add by ones by going to the right on the chart. But a refresher doesn’t hurt! Help remind them of the patterns of the chart. Practice adding problems together. I have a hundreds chart on my “Math Meeting Wall” where we practice 2-digit addition problems. I also print out a hundred’s chart on card stock and laminate it for each student. Then they can pull out their hundreds chart and use a dry erase marker to solve an equation.
It’s also so important that students get plenty of practice with using a hundreds chart to add. So I make sure to have plenty of center activities where students get extra practice. Find the activities I use here.
Break Apart
Students need to be able to see different ways numbers can be broken apart. If they see the number 64, they need to see that 64 is 6 tens and 4 ones. Then when they break numbers apart to add, then can add all the tens together, and all the ones together. It’s important that students are fluent in math facts 1-20 to be able to add the ones. To learn more about how to help students memorize math facts, read this blog post here.
Another tip with the break apart strategy is to help students draw boxes and lines, then they can remember which numbers to add. Or you can have worksheets with the boxes there for students. It helps them stay more organized as they master this strategy. Find the worksheets I use in my classroom here.
Open Number Line
With teaching students the Open Number Line Strategy with 2 digit addition, they need to see what easy “jumps” are. Jumps by tens, easy. A jump of 37, not so easy. I always start by having students make jumps of tens and then ones. Once they have mastered that they can try jumps of 20 and 5.
Students need lots of practice with open number lines. That’s why I have number line center activities to help students master this strategy. Find the activities I use here.
Tens and Ones Chart
The tens and ones chart is where we finally get to the regular addition algorithm. This is where we finally get to 2-digit addition with regrouping! But I still want students to know the meaning behind it! That is why we use base ten blocks. I print out pictures of base ten blocks and put magnetic tape on the back. Then I can move them around on the board and show students visually what is happening with the numbers when we regroup.
Giving students the tens and ones blocks can be a lot. We usually practice with them for one day. After that, we draw pictures to represent the blocks. I have my students practice that with worksheets. You can find them here.
Once they have mastered the pictures, they can use numbers and it makes learning the algorithm much more meaningful to students.
Well, there you have it! Those are the strategies I use to teach 2-digit addition. I like to make anchor charts with my students the day after teaching the new strategy as a review. It is also great for students to reference. Then I display them all so students can remember all the tools they have to solve 2-digit addition problems.
For students to be successful with 2-digit and 3-digit addition, they need to be fluent in their math facts. It can be difficult to get students to math fact fluency, that is why I made this free workbook for you! The 7 Steps to Ensure Math Fact Fluency. Download it free here.
