Mario was keeping the track of the yards gained and lost in a football game. The team lost 10 yards on the first play, gained 30 yards on the second play, and lost 2 yards on the third play. What was the net gain or loss? (SOMENE HELP ASAP PLS)

Achild has a box full of colored building blocks. she will choose one block without looking. the odds against choosing a blue block are 4/7. what is the probability of choosing a blue block? amanda is playing a role-playing game with her friends. she will roll dice to determine if her character unlocks a treasure chest. the probability of her character unlocking the treasure chest is 13/20. find the odds in favor of her character unlocking the treasure chest.