At 16 months Z loved his Preschool Prep apps. He was learning so much, but was very hard to catch on camera. That being said I was able to catch him a few times using them. If you have a child who is working on their letters, letter sounds, shapes, colors, numbers, and sight words, these apps are for them!
Also using this programs as a source of input in small children who may not be able to answer the questions is an excellent idea! I would sit with Z when he was very little and guide his hand to the right answer. So he was pulling his hands away from mine and answering himself at 16 months old.