I want to recommend you one YouTube channel that is so useful for every subject, even for maths.
One of the videos that I recommend you more is the one that talks about the measurement units. It treats the measurement units in a very interesting way, at the same time is so visual for small kids.
We have very useful tools in the class that we can use to explain all topics. In this case I decided to use the computer to show a video, but I think that the video can be moved to practice, following the steps of the video in real situations.
The thing that I most like is that their videos are in different languages, which is so useful for children and bilingual schools.
https://www.youtube.com/watch?v=wk6WSiILWvU

