Maths problem solving

Today I introduced a new idea to my top group. This group is made up of 1 stage 3 and stage 2s. I had a lot of children away so I only had 3 children today, which was a lovely way to introduce the idea. I used the lesson sequence, cars in the garage form NZ maths. I chose this context because my children are car crazy! They bring toy cars to school and I have made a BSW car game which they love.
The key idea here is making groups to 5. I originally hid the cars in the "garage" however this was too difficult and we practised many times having all cars visible for the children to grasp the idea.

 I then gave the children paper to write their ideas on. Here are some pictures of what they drew. The children in my class are getting very good a drawing their ideas but struggle to talk about them so that is always a focus of ours. The pictures they have drawn show the problem if there are 2 cars in the garage how many cars will be outside?

 At the end of the lesson on girl in the group had the grasp of the idea and was not drawing her pictures but just saying the number. She was getting the answer right instantly but not able to tell me how or why she knew. I will continue to practice this problem with this group and I will model the type of language I am wanting them to use.