Question

Yolanda needs 5 pounds of ground beef to make lasagna for a family reunion. One package of ground beef holds 2 1/2 pounds. Another package holds 2 3/5 pounds. How much ground beef will Yolanda have left

Answer 1

You can find the answer by adding the two packages and subtracting them by 5. 
2 1/2+2 3/5=5 1/10
5 1/10-5=1/10

Yolonda will have 1/10 left over.