Start by explaining to your kindergartners the basics of sorting and counting by twos. A good way to approach this topic is by bringing in examples of items that come in pairs, such as socks, shoes, gloves and other items. You may also wish to bring in several pairs of a single item to show the children that even this is a collection of many of the same item, the items can still be broken down into twos. For instance, bring several pairs of socks in various colors or a collection of buttons, no two of which are alike, to illustrate this point.
Have your kindergartners do activities to help them practice their new skills. When counting by twos, for example, children can roll a handful of dice onto a table and point out the dies that are the same, which make pairs. Another way to let children practice while also providing an incentive is by letting them practice with candy. Give students a handful of multi-colored candy such as M&Ms or Skittles, and let the children sort them into groups of two according to color. When they have practiced as long as you want, they can eat their activity.
Set up a game in which the kindergartners can participate that will help them put their new knowledge to additional practice, while also stimulating and encouraging them to take an active role in learning. Set up a table with parts of various paired items. Then hide the other halves of the pairs around the classroom. Walk the students one at a time through each item and help them find the missing half.
Assign your kindergartners homework that helps them improve their sorting by utilizing two skills. Prepare a worksheet for the children to bring home to their parents, who will need to help them find items around the home they can sort into twos. You can set up guidelines such as requiring one item for various rooms in the home, or you can allow the children to search randomly and have their parents sign off on what they find. They can bring their findings back to class and share with the class.