Models are smaller than the real thing.
So if a house is 22 meters long, a model (like a Lego version) would be how long? The scale they give says 1cm (model length) = 4 meters (real length).
How many measures of 4 meters are in 22?
22/4 = 5 1/2, so the model would be 5.5 or 5 1/2 cm long.
Hope this makes sense.