Question

how do I do this equation: John have 2 baguette and milly have 1 donut. They buy, how much do jerry have.

Answer 1

Assuming that John and Milly kindly share with Jerry, they each will have 2/3 baguettes and 1/3 donut.

Alternatively, if they do not want to share, Jerry has nothing. Or who knows, Jerry might have gone to the store and bought some baguettes and donuts of his own... or maybe a big cabbage.

The best thing to do is ask Jerry what he got...