Teach children to match pairs by having them cut different colors of papers into sock or mitten shapes, enough to have one for each child. Hand out the shapes, and ask the children to locate another person with the same color shape.
You can also cut out various shapes from one color of paper and label one set of the shapes with numbers. If you have 10 children, you will number five of the shapes from 1 to 5. On the other half of the shapes, draw one dot on one, two dots on another and so on. Have the children with the numbered shapes find the child in the room who has the corresponding number of dots on his shape.
When learning about pairs, it's also fun to have children make handprint art. Paint the palms of their hands with nontoxic paint. Place each child's two thumbs together and, while holding her fingers together, make a print on a piece of construction paper. The thumbs will make the body of a butterfly, while the fingers will form the wings. Use two thumbprints for the antennae at the top of the body.
Line up chairs in the room, and pretend that they are the seats on a train. Give each child a train ticket, made from various colors of construction paper, to decorate. Make sure each ticket has a number on it, and randomly distribute them, giving each child about three or four tickets. When the ticket decorating is over, announce to the children that you are the conductor of the Number Train. They can ride the train if they have a ticket that matches the number you call.
Have all the children cut out various shapes from various colors of construction paper. When this is complete, take out a few boxes, and have the children glue all the squares on the outside of one box, all the triangles on the outside of another box and so on. Give the children different items of various shapes to sort into the boxes. Examples are an orange for the circle box and an envelope for the rectangle box. Ask the children to explain to you why they sorted the way they did.
Using construction paper, cut out a train engine and five or 10 boxcar shapes. Laminating them will help the pieces last longer. Number the cars, and ask the children to line the cars up in order. Another way to do this would be to make a caterpillar head and circles for the length of the body.