Add Stories to Help Learn How to Add Fractions
Math can be boring. Perhaps try adding story telling to math to help liven it up a bit.
Here’s such a story:
Adventures of the STEM Club: How to Add Unlike Fractions
My name is Andre, and I’m a part of the STEM club that my sister Anna started. Our goal is to help other kids by making things for them. We’ve received a letter detailing our next mission BUT Anna insists that we MUST learn how to add fractions BEFORE going on this next adventure. I do not know why, but my sister Anna usually steers us in the right direction.
I am having a hard time learning how to add fractions though. It just won’t stick, but I’ll keep trying.
As I am working on a problem at my desk, I hear Anna call my name.
“Andre, what did you get for problem number 3?” she asks.
“I don’t have a final answer yet Anna. I keep getting different answers. I don’t know what I’m doing wrong,” I tell her.
“Ok, no worries. Let’s take this step by step. So the problem is 3/4 + 1/5. First, let’s notice that these are what we call Unlike fractions because their denominators are different,” Anna says.
“Remember, if the fractions have the same denominator, the number on the bottom, then it’s easy to add the fractions. For example, suppose your Mom buys us a pizza for lunch and cuts it into 8 slices. If you eat 2 of the 8 slices on your first serving, and then you go back and eat 3 slices later, what portion of the pizza did you eat?” Marie, another club member asked me.
“Yeah, that’s not hard to figure out. In total I ate 2+3, 5 total out of the 8 slices, so I would have eaten 5/8 of the pizza,” I answered.
“Great! That’s right Andre. So 2/8 + 3/8 = 5/8. These fractions are called Like Fractions because their denominators are the same. When the denominators are the same, to add the fractions, you just add the numerators, the top numbers, and keep the same denominator,” Marie said.
“Now let’s redo the story, but suppose Mom had bought us 2 pizzas, and out of the first pizza you ate 3 of the 4 slices. Suppose however she decided to cut a second pizza into 5 slices and you ate one of the slices. Now it’s not so easy to figure out what fraction of pizza you ate because the two pizzas were cut into different fractional parts. We have the unlike fractions 3/4 and 1/5,” Anna said.
“So now we’re back to problem number 3,” I said.
“Yes, we are, but now I’m going to show you how to solve it. The first thing you need to do is to list the positive multiples of both denominators,” Anna said.
“There’s that word again, MULTIPLES. I keep getting multiples and factors mixed up,” Tommy said, another club member.
“Ok, try to remember what multiples are this way. You remember Mrs. Ford right. How she kept having twins and triplets it seemed every other year. We thought she was never going to stop having kids. Her multiples seemed to be never ending. So remember that multiples don’t end, they go on forever. So the multiples of 4 are 4, 8, 12, 16, 20 and they go on forever just like the number of kids Mrs. Ford was having,” Anna laughed.
“So multiples go on and on and on. Multiples go on and on and on,” I sang.
“Ok, that helps. You keep skip counting on and on and on. Multiples go on and on and on.” Tommy said.
“The multiples of 5 are 5, 10, 15, 20, 25, 30, and so on,” Marie said.
“So we need the number that occurs first in both of these lists. We call that the Least Common Multiple. It’s the first multiple 4 and 5 have in common. What is that Andre?” Anna asked.
“That’s 20. So we want both denominators to be 20 now?” I asked.
“Yes, that right. We want the fractions to be Like fractions so that they are easy to add,” Anna said.
“Andre, pick a number.” Anna asked?
“Seven,” I said.
“What’s 7×1? Or 7×2 or 7×3, or 7×5, or 7×10?” Anna asked.
“Seven, fourteen, twenty-one, thirty-five, and seventy. What’s that have to do with anything?” I asked.
“Notice that the only time 7 didn’t change was when we multiplied by 1. We know we need to change 3/4 and 1/5 to fractions that have a denominator of 20, but we want the NEW numbers we change them into to still be equal to the original numbers. The way we achieve this is if we MULTIPLY the numbers by 1.” Anna explained.
“Ok, so to go from a denominator of 4 to 20, we need to multiply by 5. So that we are multiplying 3/4 by 1 though we also need to multiply the numerator by 5 as well, so that in total we are multiplying by 5/5 which is 1 right?” I asked.
“You’ve got it!” Anna said.
“Tommy, what would be multiply the numerator and denominator of 1/5 by?” Marie asked.
“So to go from a denominator of 5 to 20, we multiply by 4, so we ALSO need to multiply 1 by 4 as well, so that in total we are multiplying by 4/4 which is equal to 1. I’ve got it,” Tommy exclaimed.
“Yes, you both seem to understand. So 3/4 becomes 15/20 and 1/5 becomes 4/20. So now it’s easy to add them.” Anna said.
“Yes, now they’re easy to add. 15/20 + 4/20 is 19/20.” I exclaimed. “I can add Unlike fractions! So now what’s our new mission Anna. You said, you’d tell me the new mission when I learned how to add unlike fractions,” I said.
“I did say that. Well, here goes. Here’s a letter from a set of kids I think we should help:
Dear STEM Club, we’ve heard how you have helped so many others. In our area, it’s so hard to keep a teacher. The last teacher we had had to walk 2 hours a day to get to our school.
She couldn’t keep doing that because of a family situation. Our school doesn’t have much money to hire another teacher which is another reason why it’s so hard to find a teacher who’s willing to walk so far to get here and then work for so little money. We desperately want to become great mathematicians as we heard that you need to be good in math in order to be engineers, and we want to be engineers. We hope to one day be able to help to build up the infrastructure in our area. Would you be willing to come here for a month and teach us every thing you know about fractions. The school has found a teacher, but she’s not able to start for another month. We want to keep learning in the mean time. Thank you in advance,” Anna said as she finished the letter.
“Me a teacher?” Andre asked.
“Yes, you a teacher. All of us. You guys ready for this new STEM adventure.”
“Let’s go!” We all exclaimed.
Do you want to know what the STEM kids made in their last adventure to help other kids. Check out the book, Andre Kid Aviator, available on Amazon!
Check out this video to see how to add unlike fractions.
Stay tuned for more adventures!