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The Fraction Wars: Teaching Cross-Multiplication the Fun Way

Today, let's delve into the epic saga of fractions, where numerators and denominators battle it out for mathematical supremacy. Yep, you guessed it – it's the Fraction Wars. But fear not, for in this blog post, we will equip you with the ultimate weapon: cross-multiplication, the hero of fraction arithmetic.

What's the Big Deal with Cross-Multiplication?

Now, before we embark on this adventure, let's get one thing straight: fractions can be tricky little buggers, especially when it comes to multiplication. But cross-multiplication is here to save the day.

The Basics of Cross-Multiplication

So, what exactly is cross-multiplication? It's a nifty little trick that helps us easily compare fractions. 

Imagine you're trying to figure out which of two fractions is bigger. Instead of scratching your head and staring blankly at the numbers, you can simply cross-multiply and compare the results. 


Compare 3/4 and 2/3.

Cross multiply 3 x 3 = 9 and 4 x 2 = 8.

3/4 is the larger fraction. 

It's like sending your fraction warriors into battle armed with the most powerful weapon in the mathematical arsenal.

The Power of Visualization

Now, let's talk about the importance of visualization when teaching cross-multiplication. Fractions can be abstract concepts for young minds, so we must use visual aids that bring them to life. 

Think of fractions as delicious pizza or cake slices – each slice represents a fraction of the whole. When students can visualize fractions in real-world contexts, cross-multiplication becomes easier.

The Battle Plan: Teaching Cross-Multiplication

Now, let's talk strategy. How can we teach cross-multiplication in a fun way for our students? Let's start by ditching the boring worksheets and embracing hands-on activities.

Activity 1: Fraction Artillery

  1. Create fraction cards with various fractions. If you plan to work on fractions often, laminate these fraction cards for future use.

  2. Draw a target board with fraction values labeled on concentric circles. (e.g., 1/2, 1/3, 2/3, etc.)

  3. Form small teams of 3-4 students each.

  4. Each student will throw a fraction card at the target board to obtain their second fraction.

  5. The student will then cross-multiply their fraction card with the fraction they hit on the target board. 

    1. Example: Card: 1/2 Target Hit: 2/3. Cross-multiply the two fractions. 2 x 2= 4 and 1 x 3 = 3. 1/2 is the larger fraction.)

  6. Their teammates will also cross-multiply to help check their classmates' work. 

  7. Once the team agrees on an answer, the next teammate takes a turn.

  8. The team will continue the activity until they finish all their assigned cards or the lesson ends. 

Activity 2: Fraction Relay Race

  1. Divide the class into teams of 3-4 students each.

  2. Set up a starting line and a finish line at opposite ends of the classroom.

  3. Prepare a whiteboard or chart paper with several fraction equations requiring cross-multiplication.

  4. Each team lines up behind the starting line.

  5. When you say, "Go!" the first player from each team races to the whiteboard or chart paper.

  6. They must solve the fraction equation written on the board using cross-multiplication.

  7. Once they have found the correct answer, they return to their team and tag the next player in line. 

    1. If the student does not reach the right answer, they must keep trying until they reach the correct answer. Allow other teammates to help their peers.

  8. The next player then races to the board to solve the next equation.

  9. The race continues until all players from one team have successfully solved their equations and crossed the finish line.

  10. The first team to complete all the equations correctly and have all members cross the finish line wins the race. Provide the winning team a homework pass, an extra 3 minutes of recess, etc.

Making Learning Fun with Games and Challenges

Who says learning has to be dull and dreary? Inject some excitement into your fraction lessons with these other games and challenges: 

  • Create fraction bingo cards where students must solve equations using cross-multiplication to mark off fractions on their boards.

  • Play fraction war, where students flip over their top cards and cross-multiply to determine which fraction is greater. The player with the lesser fraction takes both cards and adds them to their stack. The player to get rid of their cards first wins the game.

Conquering the Fraction Wars

In the fractions battle, cross-multiplication emerges as the ultimate weapon against mathematical mayhem. By teaching cross-multiplication, we empower our students to tackle fraction problems with confidence and ease.

So go forth, brave educators, and may the fraction force be with you.

Written by Brooke Lektorich
Education World Contributor
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