Articles by Paul Katula



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USA Biology Olympiad Prelims

The USA Biology Olympiad, sponsored by the Center for Excellence in Education, will be conducting the initial round of tests, administered in your high school,…



Raisins in 100 ml of water overnight

We have this problem: In an experiment, a group of students placed several raisins in a container with 100 milliliters of water. They covered the…




What is a stem-and-leaf plot?

This post is directed at content developers, elementary math. I would like you to develop a Voxitatis tutorial on this topic to help parents explain…


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What is a fraction?

Update, 12 Nov 2012: Do you want to explore fractions rather than just read about them? We have developed interactive tools that allow students to…


What is a fraction?

We have developed interactive tools that allow students to explore and compare fractions with like and unlike denominators using graphical, visual models