Gave this to a 2 year old who was always pretending to be on her mobile and was able to count to five by herself (just about) but hadn't connected the words to quantities of things. After playing with it a few times one afternoon she was able to count up to 10 objects (dolls, duplo bricks, slices of bread, shoes, pencils, people, books) with understanding. Result! So proud of herself.
She also loves her 'friend' Scout, the little dog character on the phone who talks to her - her face was an explosion of disbelief the very first time he spoke to her. She's more used to toy mobiles that look more like the real thing but don't do anything beyond beeping or playing part of a tune. Takes the phone to bed with her, is able to use all the facilities and knows how to switch it on and off (a concept she has now extended to all electronic toys).
(On a related topic: she also has the Leapfrog Birthday Cake which she likes operating - switches it on and off, makes it play the song, 'blows out' the candles (they go out automatically after a pause for the child to blow them) BUT as a device for teaching how to count to five it was a complete dud. She just didn't get it. Not a toy that kept her attention for very long, more a sort of one trick thing - and it really IS one trick! As such it doesn't represent good value for money. Perhaps best suited to using at birthday parties, as an accompaniment to singing Happy Birthday.)