Math and capital cities

Examples

100

450+250-5

695

200

300+300-200+55

455

300

5*5+55

70

400

55*6

330

500

555*9-456

4539

Logic examples

100

You have 3 apples. You took 2 apples. How many apples do you have now?

2 apples (you took these ones)

200

There are 4 cats in a room.
Each cat sees 3 cats in front of it.

4 cats.