I am posting here two old MATLAB codes that date back when I was learning the language during my exchange program in Australia.
One of them simulates a vending machine using the bills and coins of the AUD currency. The values are: $0.05, $0.10, $0.50, $1, $2, $5, $10, $20, $50, $100. If you try to insert any other values, it will return and error and ask for the user to type it again. This was a really funny project that made me think a lot while doing it, since I was still learning the language.
The other one is linear system solver. It asks for the number of equations of the system and the cofficients of those equations. This saved me a lot of time back in 2015.