Use a Hundred Chart to Add Use the hundred chart to add. Count on by ones or tens. COMMON CORE STANDARD—1.NBT.C.4 Use place value understanding and properties of operations to add and subtract. Lesson 8.4 Practice and Homework Choose a way to solve. Draw or write to show your work. 5. 17 children are on the bus. Then 20 more children get on the bus. How many children are on the bus now.