Lizzy: The distance between Robin's house and the city center is 500 meters. He leaves the house to go to the city center. After he walks 200 meters he realizes that he forgot his bag. So he returns to his house, then goes back to the city center. How many meters does he walk in total?.
Me: Hmmm, let me think. I think this is the detailed solution:
He walks 200 meters first then he returns to the house. So it makes 200 m + 200 m = 400 m. The city center is 500 meters away from his house so the total distance is 400 m + 500 m = 900 m. Final answer: 900.