Which term should be added to 5y+)+(-10y) for a result of 19y

What is the sum of these mixed numbers 2 1/8 + 4 3/8

Mickey needs to cut pieces of ribbon that are each 1 meter long tie onto balloons. if he has 8 pieces of ribbon that are each 1 dekameter long. how many 1 meter pieces of ribbon can he cut

Olga used 100 ounces of flour to make 225 muffins. how many ounces of flour will be used to make 300 muffins?