This Application Problem is a part of the Lesson 9, Unit 5, Grade K. Challenge students working above grade level by extending the Application Problem and asking, "If Jenny made the same mistake representing 18, how might she show it?" and "How many more chips does Jenny need to correct her mistake?" A Pre-Kindergarten friend named Jenny drew 15 things with 1 chip and 5 more chips. Draw 15 things as 10 ones and 5 ones, and explain to your partner why you think Jenny made her mistake.