Providing an assortment of multicolored blocks might result in the infant piling together all the blocks of a specific color. This is the child figuring out how to match similar objects. To help with this, parents can bring a verbal element into the activity by identifying physical qualities like color. On a more advanced level, children can be given objects that aren't the same but go together, like a fork and a spoon, or have the child match socks of the same color among several pairs of differing colors.
Teaching basic geometry can be done over breakfast. For example, a parent can cut shapes in pancakes with cookie cutters and help the child distinguish the different shapes and understand the difference between, say, a circle and a square. This education can also happen by simply identifying different-shaped blocks or providing the child with a toy that allows him to place blocks of different shapes in corresponding holes, which also exercises matching skills.
Having small buckets or other containers of objects of different shapes and sizes can help a child understand basic principles of volume. It can begin simply, by filling the bucket with sand or water or some other relatively safe substance and then pouring it out, and then expand into pouring the substance from one container into another of a different size. Parents can do this during a bath while verbally pointing out what's going on when water gets poured out of the container. Using containers that correspond in terms of proportion allows parents to teach that, because one container is half the size of the other, it takes two scoops to fill the other.
Parents can do number activities with a variety of objects, so long as the number is small enough. This involves providing blocks or even food items that allow the child to use matching skills to identify a quantity of similar objects and helping her count them. This activity can even be done in conjunction with a meal to help count that which directly affects the infant. Performing the nursery rhyme "This Little Piggy" and announcing the number of each toe as it's grabbed also helps counting skills.