2D sorting shapes

In a car park there were 20 wheels.  If cars have 4 wheels, mini-vans have 6 and motor bikes have{...}

Launch: How could we measure the length of the classroom?  How could we measure the length of the heater? How{...}

Using a subitising video or slideshow, stop and ask what number can you see? How do you know? Can you{...}