Our brains love patterns. Patterns can be a helpful strategy and resource for young children to use. To help 1st and 2nd grade students understand the patterns of place value we often have them work with a hundreds chart. Once students learn these patterns they can learn subtraction on a hundreds chart. Subtraction on a hundreds chart actually turns out to be a go to strategy for my students to solve 2 digit subtraction problems. So I thought I would share how to teach subtraction on a hundreds chart so students get it.
I’ve learned that students find success with 2-digit addition and subtraction strategies when you teach them the mental math skills involved and emphasize common mistakes. I have a FREE guide that outlines those for each 2-digit strategy. Grab your copy here: The Ultimate Teaching Guide for 2-Digit Addition & Subtraction Strategies
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Subtraction on a Hundreds Chart
Like I said before, we first need to help students recognize and learn the patterns of the hundreds chart. Like if you go right on the hundreds chart the number is going up by one in the ones place. Or if you go down one on the hundreds chart the number increases by one in the hundreds chart. These are addition patterns on the hundreds chart. We need students to also take note of the subtraction patterns on the hundreds chart.
Like if you go left one on the hundreds chart, the number is decreasing by one in the ones place. If you go up one on the hundreds chart, the number is decreasing by one in the tens place.
To help students learn these patterns I like to use blank hundreds charts and have students fill in the numbers. I even make little hundreds chart puzzles for students to do. Find these resources here.
Learn more about how to teach these patterns here in this blog post: 7 Hundreds Chart Blank Activities To Help Students Build Number Sense
When students understand the patterns of a hundreds chart, they are then ready to learn how to use a hundreds chart to subtract.
How to Use a Hundreds Chart to Subtract
When you give your students a 2 digit subtraction problem like 86-53, you want them to find the first number on the hundred chart. I give each of my students a mini hundreds chart that is laminated. They keep it in their pencil box and can use it anytime with a dry erase marker. They find 86 on their hundreds chart and circle it. Then we look at the number we are subtracting. We need to subtract 53. We break it down into place value. 53 has 5 tens and 3 ones. We start with our tens. We need to go up on the hundreds chart 5 times to subtract 5 tens. That brings you to 36. Then you need to subtract 3 ones by going left 3. This lands you on 33, so 86-53=33.
I continue to model this to students and they solve with me on their hundreds charts. I start to ask students for each step to solve to get them more involved. Then they are ready for independent practice.
Find the student mini hundreds charts I use here.
Subtracting On a Hundreds Chart Worksheets
I like to get students up and out of their seats for independent practice. I do this with subtracting on a hundreds chart worksheets and scoot activities. I place cards with subtraction equations around the classroom. I give each student a recording page. These recording pages are nice because for each equation it gives them a hundreds chart to solve with. Students walk around the room solving the problems and getting the practice they need. Find these scoot activities here.
I set out subtraction on a hundreds chart worksheets as a centers activity to really set in this strategy for students. Find these worksheets here.
As students work with hundreds charts to subtract, they learn important patterns to place value. Using a hundreds chart is just one 2 digit subtraction strategy I teach my students. To learn more about the other strategies I teach, check out this blog post here: How to Teach Those Tricky 2-Digit Subtraction Strategies
Students are much more successful with 2 digit subtraction when they are fluent in their basic subtraction facts. I have a free guide for 1st and 2nd grade teachers to help you get your students to math fact mastery: The 7 Steps to Ensure Math Fact Fluency
Download your free copy here.
