I loved the effects in using Arithmetic, here is the statue set against Rollie's flower photo using Subtract as shown in the screenshot.

I used my own photos for the rest of the lessons.

I didn't take screenshots of the Curves settings but it transformed a rather dark picture of the roof of the long hallway in the Vatican museum, Rome.

Finally I used the histogram on a photo I had of the inside of the Pantheon and it was incredible to see how much detail it brought out to show the roof carvings. Again I'm sorry I forgot to take a screenshot of the settings!