They decided to hold the party in their backyard. They have 3 sets of tables and each set has 28 chairs. There are also 42 chairs extra. How many chairs do they have for the guests?
There are 3 sets of tables and each set has 28 chairs. 
That means that there are 84 chairs in total for the sets of tables. 
There are also 42 chairs extra. 
That means that there are 126 chairs in total for the guests.