This activity helps to involve families in teaching children math skills. Label an empty plastic jar with the words "Estimation Jar." Every Friday, send the jar home with a different child and a note to the parents. Ask the parents to fill the jar with random household objects such as crayons, milk-top lids, marbles or small toys. Give a limit to the number of objects based on the current counting skills of your class. Have the child return the jar on Monday. Throughout the week, let children guess how many objects are in the jar by writing the amount on sticky notes or putting their guess next to their name on a chalkboard. At the end of the week, have a child count the objects in the jar. Compare the number to the estimates that the students made throughout the week.
This activity has students guess how tall they are using different visual measurements. You can pick a different measurement each month to incorporate different themes. For example, in February, you could do "How Many Hearts Tall Are You?" Have students decorate construction paper hearts -- or whatever other object you choose -- that are all made from the same template. Then have them guess how many of the hearts stacked up would equal their height. Tape the hearts on top of each other against the wall and have students measure themselves.
Fill a container with candy. You can use Halloween candy in October, flower candy in May or any other type of candy to match what you are doing in your classroom at the time. Have students guess how many pieces of candy are in the jar. The person whose guess is the closest wins the candy. Be sure you are aware of any food allergies in your classroom and do not use candy that a child is allergic to.
Set up a station near a sink where two children can work at a time. Have a clean, empty 12 oz. beverage can, a clean, empty 2-liter bottle and a small paper cup. Have each team guess how many cups of water it will take to fill the can and fill the bottle. Then have one child fill each container while the other counts the cups. Have them compare their estimates with the actual amount.