Question

For it says sales tax in the word problem do you need to add or subtract?!

Answer 1

When you go to the store, pick up some stuff from the shelves,
and take it to the check-out, the checkout lady adds up all
the prices of the things you bought, and then she ADDS the
sales tax to the sum.  The amount of money you pay is always
MORE after she adds the tax than it was before she added it.