Adeciliter is how many times larger than a millimeter?

Milliliter  centiliter  deciliter  liter   dekaliter   hectoliter kiloliter

All related by 10's   every move to the right is 10x larger than the one to its left

Since deciliter is two steps away from milliliter it is 10 x 10 or 100 times as large.

If the question is meant to be a trick then the answer is 99x larger.  

It should read "A deciliter is how many milliliters"  ofr "a milliliter is how much of a deciliter?"
 Once you say larger than you could be confusing subtraction with multiplication.  How much larger than 30 is 3?  Answer is clearly 27.  How many times as large as 3 is 30?  Answer is clearly 20. How many times larger than 3 is 30?  H?  Which one of the two does he mean?
I am sure your teacher meant you to consider multiplication, but just in case, I included the "trick" answer.

An atom that has fewer electrons that protons is called a positive ion.