He is a student at Le Loi school.

We're saving money to buy a new house.

1. subjects/ you/ study/ at school?

=> How many subjects do you study at school?

2. hours/ you/ sleep/ every night?

=> How many hours do you sleep every night?

3. money/ you/ have/ in your bag or pocket?

=> How much money do you have in your bag or pocket?

4. water/ you/ drink/ every day?

=> How much water do you drink every day?

5. students/ in your class?

=> How many students in your class?

2015 - ( x + 1 ) : 3 = 2000

          ( x + 1 ) : 3 = 2015 - 2000

          ( x + 1 ) : 3 =        15

            x + 1        =   15 . 3

            x + 1        =      45

            x              =     45 - 1

            x              =       44