In 1 & 3, all of your articles are in the correct place.
In 2, it could be either "the" or no article, but I think that no article is best here.
PS: It is the convention in English speaking communities to put currency symbols such as $, €, £ etc. before the value and symbols for pence, cents etc. after the value. Also, the point "." is used to mark the "radix point" (i.e. where whole numbers turn into fractions) and not the comma.
[Not a teacher]
Student or Learner