Judith Kerr's One Night at the Zoo is an inspired counting book, illustrated with the charm that made her Mog books and The Tiger Who Came to Tea such a hit. My own all-time favourite Kerr is Why Mrs. Money Missed the Ark, both for its moving story of what a mother goes through to keep her family fed at all costs, and its animal pictures. The animals here take part in a "magical, moonlit night in the zoo" which sees elephants flying, lions doing card tricks, flamingos turning blue and more, all in rhyme. The expression on their faces is captivating; this is a great way not only to teach a little one how to count but to enjoy a visit to the zoo.
Loads of silly rhymes, good pictures and counting opportunities. Just the right length for my 20 month old, and I enjoy reading it too. He loves pointing out the animals that didn't make it back to their cages in the morning.