This Application Problem is a part of the Lesson 2, Unit 4, Grade 2. Susan has 57 cents in her piggy bank. If she just put in 30 cents today, how much did she have yesterday? This add to with start unknown problem gives students a chance to apply their new learning. It also provides an opportunity to work through a common mistake; many students will add and give the answer 87 cents. Encourage students to draw a tape diagram to show what is known.