Maddie, Luisa, and Amy counted their books. Maddie had 15 books. Luisa had 18 books. Together, Amy and Luisa had 9 more books than Maddie. How many books did Amy have?

Greg and Brad started reading their books at the same time. Greg read 18 pages a day. Brad read 26 pages a day. After two days, how many more pages did Brad read than Greg?

Greg's mom made some cookies for the family. The cookies were so huge that she decided to cut them in half. Greg ate 4 halves and his brother, Brad, had 6 halves. There were 18 halves left. How many whole cookies did Greg's mom make?

Eric has two pieces of rope. One piece is 10 inches longer than the other. The total length of the two pieces is 40 inches. How long is the shorter piece?

Ethan and Frank went rowing. Ethan rowed the boat from 10:50 to 11:15. Frank rowed the boat twice as long. How long did the boys row the boat altogether?