(5x210)+41,790= 42,840 initially
Okay so
5 tree cut down
So now he have 41 790 orange so he have less that initially
We have to found how many he had before the 5 tree were cut down
And don't forget that each tree produces 210 oranges
So you look for how many orange he had lost (5x210)
And then addition what you have with 41,790
I hope you understand