Mathematical concepts; In order for the children to conceive the length and proportion we play various games:
Handling of objects is the key to knowledge, as Piaget says. Observation and comparisons come afterwards.
I would like to share some of my projects with you, just because they helped children to understand and enjoy mathematics.

Height
We measure ourselves against the wall. We have created a measure with centimeters and we put our names in the centimeters we reach.

First we measure ourselves barefooted, and we see our height.
After some months we measure ourselves and put the new results. The difference we take home in a piece of colored tape.

This activity triggers a lot of comparisons and observations.(why younger children were taller than older, why some gained more hight than others e.tc.)