Teaching kids to add fractions has so many parts to it. It’s like a clock with all the cogs turning, and for some kids the cogs can get a little messed up. One way to make sure students are ready and have a solid foundation with fractions is by giving them a lot of practice each step of the way. They need to see fractions many times and they need to feel comfortable during the practice. For some kids their math ego is pretty fragile and that’s why I like to use games. When kids play games they’re more likely to be okay with making mistakes. This post has ten awesome games and activities to get students the practice they need finding the least common denominator.
Finding the common denominator is one of the key skills students have to have to add and subtract fractions. You can find different strategies for helping students find the common denominator. I have students first look at whether one of the denominators is a factor of the other one. If that’s not the case then we look at whether the denominators are multiples of 2, 3, 5, or 10. If none of that helps, then we use the what we call the butterfly method. You can see an anchor chart teaching the butterfly method here.
Once students have these strategies in their tool box, they need lots, and I do mean lots, of practice. Here’s a list of practice activities for finding common denominators:
Let’s dive in
In this post you’ll find a varieties of activities on this list. Some work well for small groups, while others are perfect for center activities. Also, a couple of them work as whole class activities. You can look through them and find what works for your class and your students.
Kids love doing math mazes. Usually, I have students complete the maze at the beginning of math time, and then they check it with me. If something isn’t correct, then I have them fix it. We use mazes as a warm-up, but they also work well as a center or homework. You can print them on paper or put them in SmartPals (dry erase sleeves) so that they can be used over and over. I’ve never heard students complain about having to do a maze.
These three common denominator mazes give students a ton of chances to find the common denominator between two fractions. You’ll find a variety of fraction types with a lot of different multiples. For the most part the highest common multiple isn’t bigger than 15. You can use these mazes one time at the beginning of this unit, or use them again later in the year as a review. (I even reuse the same mazes months later for cyclical review. Students don’t remember answers, and it’s a great way to review.)
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If you want your students to have a chance to talk while finding common denominators, then look no further. Paper chains work in my class because students love working together. They are given 12 strips, each with a problem and the answer to another problem. Then, students put the problems in order. Students work together, usually in partners, when doing this work. I love hearing them talk about their answer choices.
When students finish putting all 12 strips in order, I have them check their answers with me. If they don’t need to fix anything, then they get to make the paper chain. If they have a mistake, then i can let them know right away to go back and fix that.
In this particular paper chain students get a chance to find the answers to 11 common denominator problems. They need to have some practice with this skill before they work on this paper chain. This activity also makes a great center or station assignment.
Getting technology into the classroom can come in many forms. One way that I like a lot is through QR codes. If you aren’t sure what a QR code is, here’s an example:
That little code gets scanned by a phone or tablet and takes you to a website, reveals text, or in this case shows the answer of a math problem. In this Common Denominator QR code game students play against a partner or in a group of three. They answer questions and check their answers with the QR Code. This gives them immediate feedback on how they’re doing. Then students check a different code and it tells them how many points they have earned. The kids love this part. They don’t know how any points they’ll get and they think it’s pretty funny earning random amounts of points.
Worksheets and the Target Game
There’s several websites with common denominator worksheets. This website contains a ton of worksheets for this topic at a variety of levels. It just helps you so you don’t have to keep thinking of different fractions- they’re already created for you. Typically, we don’t do worksheets in my class. However, we do use the questions from the worksheets and play games with them. This set of worksheets would work really well with the target game. Learn more about the target game in this post.
I love this Fruit Splat game. That’s probably because I love playing Fruit Ninja on my phone. The Fruit Splat game resembles Fruit Ninja in a lot of ways. Students are given two fractions and they need to find the least common denominator that’s floating around on a fruit. When they find it, they slice it and the game makes an awesome splatting noise. I love that they have three levels and let students speed up or slow down the game. What amazing differentiation built into the game, and the teachers doesn’t have to do anything. I use it for fast finishers or as a center activity. Your students will keep asking to play this game.
This Snowball Fight Game doesn’t have fractions, but it does have students finding the least common multiple in a fun way. Two numbers are displayed on the screen and you have to choose the person with the right least common multiple. If you are right, you hit the person with the snowball. If you get it wrong then you get hit. Your game “life” is measured with a thermometer and you want to keep it warm. Such a fun way to practice this skill!
Common Denominator War is a game you can have partners play to practice finding the lowest common multiple. You can find the directions at this blog post. I would change it and play this game with fractions instead of just multiples. This blog post from Math File Folder Games has a series of variations that you can use with your students. Personally, if you’re going to play this game based on speed, it’s super important to make sure that the partners are students who work at about the same speed. You can get a lot of practice in a short amount of time with this game, making it a great addition to math class.
I love this XFactor game from Cool Math because it seamlessly integrates math with the game. Students play this game online. In this game, students practice finding making a target numbers by finding the multiples that make that number (this link goes to the game for “32”, but you can choose another number). While it’s not specifically practicing finding common denominators, it’s a great game to help students see the patterns in how numbers go together, super helpful when they need to find common denominators.
To play, students choose a number and that becomes the target. Then, they have to shoot at a number that, when multiplied, makes the target number. It gives students a ton of practice in a short amount of time and it’s super fun. This activity works as something students can use while learning about common denominators. They can also continuing playing it and practicing this skill all year long. When students finish one level, it sends them on to the next level. The game board looks cool and it makes students just want to keep going with this game.
Sometimes you want an activity to play with the whole class. Jeopardy is one of my go to’s for whole class review games. I don’t have students play in teams, though. When they play in teams I find that only a few students do the work. When we play, everyone is their own team. They keep track of their own points. This Jeopardy game has three types of questions. Students will see questions for finding the LCD between two fractions and between two mixed numbers. Then, there are some questions about the process of finding the LCD.
Not everything that you do has a to be a game. I think that giving kids an opportunity to look at common mistakes can help them not make the same mistakes. With the diagnosis the problem strategy, students have to look at a worked problem that has a mistake and explain where the person went wrong.
Then, students prescribe a solution by completing the problem themselves. This activity works great as an anticipatory set and is little prep for the teacher. Grab the free Diagnose the Problem form here. You can also do this activity over and over with other topics throughout the year.
Try one thing
So, now it’s your turn to take one of this activities and try it in your class. Maybe you can’t do them all, but I hope you’ve found something to try with your students. These activities are sure to add a little more engagement to fractions practice and get students the repetitions they need to gain confidence with finding the lowest common denominator. Students love novelty and fun, so they’ll appreciate you mixing it up and they’re sure to get so much better at finding the least common denominator.
Thanks so much for reading. Until next time!
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