Natural Blogarithms

Sally has five red cards numbered 1 through 5 and four blue cards numbered 3 through 6. She stacks the cards so that the colors alternate and so that the number on each red card divides evenly into the number on each neighboring blue card. What is the sum of the numbers on the middle [...]

Form a number from the digits 0 to 9 such that the first digit is divisible by one, the first two digits form a number that is divisible by two, the first three digits form a number that is divisible by three, and so forth.
I’ll post my solution in a day or two.
HT: QYV [...]

A couple of days ago, I posted the following puzzle:
There is a ten digit number where the leftmost digit is also the number of zeros in  the number, the second leftmost digit is the number of ones and so forth until the last digit (or rightmost digit) is the number of nines in that number. [...]

Ok, so I know that several of the readers of this blog will enjoy this, several others will groan as they read, and many others will just roll their eyes at the lack of humor below.  I’m posting anyways.
And for the record, at one time, I have laughed out loud at every one of [...]

There is a ten digit number where the leftmost digit is also the number of zeros in  the number, the second leftmost digit is the number of ones and so forth until the last digit (or rightmost digit) is the number of nines in that number. What is this number and is it unique?
I’ll [...]

Number Sense in fourth grade.
(Continuation of a series from a while back… –> Mathematical Moments)
In the fourth grade, I was first given the opportunity to participate in a UIL competition that I really enjoyed.  In Texas, there are quite a few academic contests which are part of the UIL (University Interscholastic League), and by [...]

Well over two years ago on this blog (have I really been around that long?), I posted a link to a story that Sudoku had been solved.  (The original link to the Math-Forge Story is broken, so here in alternative version of the story.) While just about every computer scientist and programmer I know [...]

Following in the vein of my earlier post, here’s another oldie, but goodie:
[HT: SoftwareCraft]
CLEARLY: I don’t want to write down all the in-between steps.
TRIVIAL: If I have to show you how to do this, you’re in the wrong class.
OBVIOUSLY: I hope you weren’t sleeping when we discussed this earlier, because I refuse to repeat [...]