Tag Archives: sets

Family Regrouping

Two sisters, two parents, two cousins, and four grandparents, all met up at the park (true story).  During the car ride home, one of the sisters (lets call her Katie), exclaimed, “There were ten of us at the park.”  The … Continue reading

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A bit of Set Theory

Katie and I joined my sister’s Golden Key Russian School – Katie attends and I help out my sister with the math classes.  We hope to write semi-detailed descriptions of the lessons on the school’s blog, but here I will … Continue reading

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One-to-one correspondence – Not always obvious to kids!

There are some very hard problems in combinatorics that involve showing that there is a bijection (one-to-one correspondence) between two set of objects, thus showing that the two sets have the same number of elements.  On the other hand, we … Continue reading

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