Search engines are imperfect. A portion of my visitors ask a specific question, but I am answering a different one. Google isn’t yet smart enough to see the subtleties, and directs them to HowTutorial.com. I hope they found what I wrote interesting, but I admit they must remain unsatisfied.

This is the second time I will be collecting questions that need answers from my search logs. The first time, after a series of posts about math shortcuts, I wanted to help someone with a misconception. This time is two trick questions.

**Question:** What is one number that’s divisible by everything?

**Answer:** That is a trick question. Instead of trying to solve for such a number, let me tell you that the number is **zero**. Through a little thinking, you can agree that it is true. 1/4th minus 1/4th equals zero fourths. That is 0/4ths. No forths at all. Nada. Zero. Zero divided by 4 is zero. 0/2=0, 0/9299292929=0, zero divided by everything is zero. The only exception, is 0/0 = undefined. So with that exception, zero is the one number that is divisible by everything.

**Question:** What number is divisible by all 9 numbers 1 to 9?

**Answer:** Well since we are looking for any number that has this property, and not just the smallest, we can simply multiply all nine numbers together. 1 x 2 x 3 x 4 x 5 x 6 x 7 x 8 x 9 = **362880**. That is one answer. If you want the smallest answer, then let us try harder. If we are going to multiply by **9**, then we don’t need to multiply by 3, since 9 already has a factor of 3. **8** has factors of 4 and 2, so we don’t need to include them either. **7** is prime (no factors other than itself and 1), so we keep that. 6 has factors of 2 and 3. We took care of both factors already since 9 and 8 already had those factors. But that also means the 3 factor for 9 and the 2 factor for 8 will give us divisibility by 6. So we don’t need to multiply by 6. **5** is prime too, and not a factor of any larger number we already included, so we need it. And we already got rid of 4, 3, and 2. 1 doesn’t change anything, so keep or skip it… 9 x 8 x 7 x 5 = **2520**, which is then the smallest answer. But wait, is it? The question above already showed us that zero is divisible by everything! So the smallest answer to this question is **zer0**. Another trick question.