Tuesday, January 15, 2013

How many positive integers less than 101 are not div by 2 and not div by 3?

Instead of posting this innocent little combinatorial problem to Twitter like I've been doing for the past 2 years, I decided to post it here so my readers will know MathNotations is not extinct!

Comments about this problem:

1) What would be an easier variation you might first pose? Oct 2009 SAT, Prob 17, "grid-in"!

2) To those who  have been teaching these types for awhile, SHARE your strategies!

3) A Black Box Soln:

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