Sharon was taking an important math exam. It was worth 25% of her final grade. She really wanted an A in the class. She had been doing well so far. She finished half of the problems in just 20 minutes. Then the worst thing happened. The batteries in her calculator ran out. She could not get any of the answers without her calculator. She raised her hand. Her teacher walked over to her. ""Do you have an extra calculator?"" Sharon asked. ""Nope,"" the teacher said. ""Can I use someone else's calculator when they're finished with the test?"" she asked. ""Fine, but next time bring extra batteries,"" her teacher warned.