I need a simple solution that a 5th grader can understand.Would appreciate your help! Thanks in advance!
Ron and Matt both bought postcards during their trip to New Zealand. At the end of the trip, they decided to trade. Ron traded half of his postcards for 9 of Matt’s postcards. After that trade, each of them has 21 postcards. How many postcards did Ron have before the trade? How many postcards did Matt have before the trade?