The difference of 7 and a number n

When i add money am i supposed to make it like this 7+12 or 7.00+12.00 because i got 19 dollars for my answer

Ajar of gumballs contains 4 reds, 2 greens, and 6 blues. what is the probability of getting two blues in a row without replacement?

Tom wants to order tickets online so that he and three of his friends can go to a water park the cost of the tickets is 16.00 per person there is also a 2.50 one-time service fee for ordering tickets online write an expression in term of n that represents the cost for n ordering tickets online