Using the three images, explain how subtraction on the bus work. The first image shows how many passengers are on the bus as it arrives. The second shows how many passengers exit the bus at the stop. The third image shows how many passengers are left on the bus as it leaves. You can determine this third image total by taking away the number of exiting passengers from the total number of passengers from the first image. Ask students to name which number is the first number of the subtraction problem (minuend) which is the second number of the subtraction problem (subtrahend) and what is the total, or difference. Tell students that they can check their work by adding their total (difference) and second number (subtrahend) together.

Next practice two more bus examples on the interactive whiteboard. Explain to students that the images will now stay the same- you can have all the information in just one image. Practice this with two bus examples and show students that they can also solve using the bus method even when they can't count the individual passengers, but are given numbers to represent the number of passengers on the bus. Tell students that they can also split their second number (subtrahend) to make subtraction easier when you have to cross ten. Practice with the students.

To check that students are able to subtract numbers to 20 using the context of a bus ride crossing ten, you can ask the following questions:

- What are the steps to solving a subtraction problem on the bus?

- What does the first number in the subtraction problem represent?

- What does the second number in the subtraction problem represent?