To answer this problem, you need to divide 6 by 2/3. Remember that whenever you divide a number by another number, you are asking, "How many times does this second number fit into this first number?"
6÷

=?
When you divide a number by a fraction, it's actually like you're multiplying it by the reciprocal. Here's a simpler example:
3÷

=9
If you think about it, this makes sense because 3÷9=

.
So, in this case, 6÷

=6×

.
To solve this, multiply 6 times 3 (=18) and divide by 2 (=9).
6÷

=9