Betty collected 400 food packages for charity. she gave g packages to an orphanage, and distributed the rest equally among 4 charities. how many packages did each charity get?

So this is an equation.
The starting value is the given value 400.
She gave g packs to the orphanage, so she now has 400-g packages. 
Then she divides that by 4 and gives to 4 different charities.
The answer is (400-g)÷4
Hope this helps!