This Application Problem is a part of the Lesson 33, Unit 5, Grade 4. Jeannie's pumpkin had a weight of 3 kg 250 g in August and 4 kg 125 g in October. What was the difference in weight from August to October? In Grade 1, students relate subtraction to addition by counting up. For example, 12 - 8 is easily solved by counting up from 8 to 12: 8, 9, 10, 11, 12. As students become more adept at using a unit of 10, they see they can get to the next ten, rather than counting by ones.