Neat walkthrough!

Last year I actually made an applied-CoreML app to solve sudoku puzzles where MNIST came in very handy.

I wrote about it here: https://blog.prototypr.io/behind-the-magic-how-we-built-the-...

"Apple ... provides a ... helper library called coremltools that we can use to ... convert scikit-learn models, Keras and XGBoost models to CoreML"

Awesome.

As someone with not much experience in ML, how to handle when there is no number present or if a number is present?

The scrollbar distance confirms a suspicion that I've held for some time: that writing a machine learning algorithm is of similar complexity to developing an iOS app in Xcode!