To convert meters to kilometers, you need to divide by 1000 since there are 1000 meters in 1 kilometer.
Given that the distance from Rodrigo's house to his grandma's house is 12,000 meters, to find out how many kilometers he will travel for the round trip, you need to divide this distance by 1000:
12,000 meters ÷ 1000 = 12 kilometers
Therefore, Rodrigo will travel 12 kilometers for one round trip visit to his grandma's house and back home.