Why Learn Conversions???

sale sign


“The journey for an education starts with a childhood question.”     – David L. Finn

As I played “Conversion Concentration” with a small group of students at the Games Station, one student asked the inevitable question about conversions,

“Why do we have to learn this stuff?”

These students had been completing a conversion chart every week since the beginning of school, but their teacher knew the value of partnering conversion memorization with meaning, so before the students began creating conversion charts, he had the students use manipulatives at the Manipulatives Station to help them develop a concrete understanding of the relationship between fractions, decimals, and percents.

The week after experiencing conversions concretely at the Manipulatives Station, their teacher began to have them play games that used the visual representation of the fraction, decimal, and percent partners. I just happened to be there on a day when they had moved to the abstract and were playing “Conversion Concentration”  to help them memorize the conversion “facts.”

“Conversion Concentration” asks pairs of students to match the fraction to the equivalent decimal to the equivalent percent. If a pair finds at least one match, then they take those two cards and win a point. If a pair finds the third, then they win 5 points. t

[Play Conversion Concentration with your students. Download Conversion Concentration Directions, Conversions, Sheet One; Conversions, Sheet Two; Conversions, Sheet Three; Conversions, Sheet Four]

Every card that is turned over remains visible for the next pair. This encourages constant review of the cards and comparison of the possible matches between the fractions, decimals, and percents. To add challenge to the game, a timer can be used and each pair has only one minute to find the matches.

The steps this teacher had used, concrete to pictorial to abstract, must have been effective, because these students were faster than I was at matching the three cards and winning the 5 points—something they absolutely loved!

But let’s get back to that question, “Why learn conversions?” Recently, a store provided the perfect example and I shared my story with the students. Two of my children and I were going into a store and were looking through the carts of seasonal items that had been marked down for a quick sale. Several of the carts held big bags of candy and had a 75% off sign on them. This was a bargain, so I got several bags.

At the check-out register, the cashier scanned the first bag of candy. It rang up at $3.24—NOT the sale price at all! I mentioned the 75% off cart and she agreed that it was on sale.

Cashier, “But, I have no idea how much to charge you. If you can tell me the price at 75% off, then I’ll give it to you for that amount.”

I looked around the group of students and asked them if it was worth my mental energy to calculate how much the items really cost at 75% off. Everyone enthusiastically agreed. So, I asked them, being experts in conversions, to share how they would figure out the discounted price of the items—knowing what they did about conversions.

Student 1: “Easy. You just convert the 75% to a fraction. The fraction is ¾. You know that the total number of parts is 4 so you divide $3.24 by four.  That will give you 81¢.”

Student 2: “How did you get 81¢?”

Student 1: “Again, easy! You divide 32 by 4 and get 8. I still have 4 cents left, so I divide that by 4 and get 1. That’s 81¢.”

Student 3: “What’s that called when you do that?”

Student 4: “Front-end estimation. Remember when we learned how to do that a few years ago? What do you know—we’re using that stuff, too!”

This group of enthusiastic and engaged students were amazed at the practical and meaningful use of what they had been learning in math. We talked about discounts and ways to use conversions and mental math in stores every day. They never dreamed that they could actually use conversions except for regurgitating information on a test.

The most genuine statement from a student?

“You saved over $2 a bag for that candy. That’s why we learn conversions—so our moms can buy us more candy!”

“It’s not that I’m so smart, it’s just that I stay with problems longer.”    – Albert Einstein

Thanks to this teacher, these students have learned conversions, a little bit more about personal financial literacy, and, as Albert Einstein stressed…they aren’t just smart, they now have the tools to stay with the problem longer!