Jonathan serves up plenty of fun in this month’s Carnival of Mathematics. And he will be hosting the *Math Teachers at Play* blog carnival in two weeks — submit your entries here.

Normally a Carnival of Mathematics opens with a discourse on its ordinal. But 69?

It is 1000101 in binary, 1011 base 4, 105 base 8, 45 in hex… If we used 32 as a base? 25. And that would be 15 in base 64.

69 is odd. But there are as many odd numbers as there are ________. I still love that! It is one of a bunch of surprises that Dave Richeson lists at Divisio …

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via JD2718

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