Rachel picked 19 apples from her tree. If the tree had 37 apples initially. How many apples are still there on the tree?
1. Rachel picked 19 apples from her tree. 
2. If the tree had 37 apples initially, 
3. How many apples are still there on the tree? 

We can solve this problem by subtracting 19 from 37. 

37 - 19 = 18 

So, 18 apples are still there on the tree.