Krypto is an activity I learned about at a conference where Dr. Lola May presented (in like 1993, I think!). I didn’t realize until a long time afterwards that it was a commercial game that could be purchased 🙂 I believe it’s also available as an app now.
I’ve used the game idea from time to time, following the rules as laid out in the book I got at the conferece. Krypto can be played with whole numbers or fractions (and with positive and negative integers as well, I’m sure!).
Playing Krypto With Fractions
1. Choose 5 common fractions, with denominators of halves, thirds, fourths, sixths, eighths, tenths or twelfths.
2. Students add, subtract, multiply, and/or divide the fractions to make the 5 fractions equal the target number of 1.
3. Students receive points for meeting the target number of 1. For example, if they reach the target of 1 using only 3 numbers, they get 300 pts; 4 numbers = 400 pts; if they use all 5 numbers, they get 1,000 pts. You can set up the point system any way you’d like. Krypto can be used as a team effort/team game or individual enrichment activity.
This math activity is a fantastic way to provide practice with all the fraction operations. It promotes problem solving and persistence.
Fraction Krypto Example
When I use this activity, I put fraction cards on the board and leave them for as long as I need (and move them if they get in the way!)
- One solution for this set of fractions in the picture could be 3/4 x 2/3 + 1/2 = 1
- This solution uses only 3 fractions, so that would earn 300 points.
- Another solution is 2/3 + 2/6 = 1; but that’s only 2 fractions. You might consider giving points for using just 2 fractions, until students get the hang of it.
Can you make the 5 fractions equal 1?
Krypto With Whole Numbers
1) Choose 5 numbers (from 1-20)
2)Choose a target number between 30 and 50).
According to the book I received at the conference (yes, I still have it:-) computers at Berkeley, CA showed that a 5-number solution can be found 86% of the time when the 5 numbers and the target number are chosen randomly.
Example:
- Choose 3, 4, 7, 12, 14
- Target number: 42
- Solution (using 4 numbers): (12 – 4) x 7 – 14 = 42
What other solutions can you find?
If you haven’t used Krypto with either fractions or whole numbers, I hope you’ll give it a try.
Check out the course, Fractions: From Foundations to Operations.
