Toddlers understand just a few mathematical concepts — notably, one, two, and lots or more. They can't really distinguish between very small numbers. Although two-year-olds might pronounce numbers from one to ten (and are likely to do this by the time they turn three), they don't connect the words with actual amounts.
Like the value of using long words regardless of whether your two-year-old understands, you should feel free to count items for her out loud, such as the food you get at the grocery store or toys you're playing with. Just don't expect her to be able to count along with you. Introducing her to basic arithmetic is helpful and will give her another way of understanding the world around her.
Reading numbers on a page is difficult for children because, as with letters combined to form words, they represent something abstract. So when you are teaching your two-year-old how to count, hold your fingers up or line up toys so she can connect the numbers with their meaning.
At two, children enjoy playing with pretend money, clocks, and watches because they are mimicking your behavior, even if doing so makes no real sense to them. Like letting them wash dishes or play with dolls, this imaginative play is beneficial, enabling them to familiarize themselves with adult notions and concerns. You can cut money up out of green construction paper and give your two-year-old one of your old wallets. Then let her shop in the house and pretend to buy her toys.
If your child is interested in a clock, show her how to wind it and how the alarm goes off at a certain time. Many children like stopwatches, too, because they can click them on and off. Remember, concepts of time and money do not really start to make sense to a child until she is around five. Nonetheless, your two-year-old listens to what you have to say about money and time even if she does not understand their meanings.