I have created an IJulia (Jupyter) notebook showcasing automatic differentiation using multiple dispatch in Julia. More notebooks may be uploaded in the future, especially if there is demand.
I also teach Olympic Math for Grade 4 students at the Grand River Chinese School. This page contains samples of some of the material taught.
Here is the lesson plan for the Number Theory unit, which covers (at a basic level) parity, divisibility, primes, the fundamental theorem of arithmetic, GCDs and LCMs, the Euclidean algorithm, and an introduction to modular arithmetic.
Some parts of this lesson plan are incomplete, but it is mostly mature and complete.
Here is the draft lesson plan for the Measurement unit, which covers angles, lines, polygons, length, area, and units of measurement. Note that this lesson plan is a rough draft and is incomplete.