Stumpers 3

1.  Taking three as the subject to reason about---

A convenient number to state---

We add Seven, and Ten, and then multiply out

By One Thousand diminished by Eight.

The result we proceed to divide, as you can see,

By Nine Hundred and Ninety and Two:

Then subtract seventeen, and the answer must be

Exactly and perfectly true.

2.  Write the numbers 1 through 10 using exactly six 5's.  You are allowed to use any mathematical symbols you know.

3.  If you take the product of any three consecutive integers and then add the middle number, the result is always a perfect cube (of the middle number).

For example,  4*5*6 +5 = 125 = 5^3.

Why does this work?  Prove it algebraically.

4.  If  two dogs can jump across a ravine six feet wide, then how wide a ravine can four dogs jump across?