Could you say more about what you want to accomplish? Numpy and Sympy are toolkits which are used by other programs. You can write Python programs in Leo, run them, and display the results in several ways, if that's what you are thinking. You can use Mathjax to make good-looking equations.
One way to do this is to take advantage of the Viewrendered3 plugin. You can mix text and program fragments somewhat as you can with Jupyter (Jupyter can do a lot more, but VR3 can be much more convenient especially for Leo users).
I've attached a small example of a notebook. It uses numpy to create some data, plots the data, and then for good measure renders an equation. You will probably need to create some settings nodes to myLeoSettings for Mathjax to render the equation. Directions are in the documentation for the VR3 plugin. In VR3, make sure to check the Entire Tree view option before executing the notebook.
If you don't know how to find the documentation, add new settings, or enable the plugin, just ask here.