Keenan gives tisha half of his strawberries. tisha keeps 4 of the strawberries she got from keenan and gives the rest to suvi. write an expression for the number of strawberries tisha gives to suvi

At start Keenan has x strawberries. He gives Tisha x/2. Then Tisha keeps 4 strawberries and gives Suvi the rest. If y is the number of strawberries that Suvi gets:
y = x/2 - 4.
For example: Keenan has 20 strawberries. He gives Tisha 10 and Tisha gives Suvi 6:
6 = 20/2 - 4 
6 = 10 - 4