If you triple 4 and subtract 2 each day, how many day until you have zero?

I'll take it that it's implied that we're only subtracting 2 everyday, and only triple 4 once.

So, let's break this down.

Triple 4. This means to multiply by 3, or self-add 4 three times.

It should look like this:
4 + 4 + 4
or
4(3) or 4 • 3.

Let's go with the addition path, as it's easier to understand.
4 + 4 + 4. (Total of three 4's)
4 + 4 = 8 (Get rid of two 4's)
We are now left with one 4.
Add it to our current sum, 8.
8 + 4 = 12.

We now have 12 total.
However, since we're subtracting 2 EACH day, we'll have to divide 12 by 2 to find how many days until we reach zero.
12 / 2 = 6.

It will take 6 days for you to have zero.

I hope this helps!