Teaching estimation strategies helps children determine approximate  but close  answers to problems. You can teach your students how to find a number that’s close to the right answer through activities that involve money, counts, lengths and sizes.
Estimate a Purchase

Give a child an ad from a grocery store or toy store. Challenge the child to "shop" with a set amount of money and to "spend" as close to the entire amount, without going over that amount. Provide a worksheet for the child to list each item's estimated amount. For instance, if a gallon of milk is listed for $3.95, teach the child to keep a running total based on a rounded value. In this case, the child would write $4.00, rounding up to the nearest dollar. After the child has listed the estimated value and has approached the final total amount, ask the child to write the actual cost of each item on the list. Ask the child to add the actual amounts so he can determine how close he got to the estimated total. You can repeat this activity with different ads to improve a child's ability to round numbers and predict a final cost.
Estimating Value

Teach a child to estimate the value of a purchase on the shelf of a store. Provide two examples and ask the child to decide which item has the best value for the money. For instance, a box of six granola bars is priced at $4.00. Single granola bars sell for $.75 each. Ask the child to decide which item represents the better buy by estimating the price of the boxed granola bars if sold individually. Alternatively, the child could estimate the cost of six single granola bars and predict which purchase would be the better buy. For additional practice, have her write down a math equation to represent the predicted costs, both estimated and actual amounts.
Estimating Length

Challenge a child to estimate the distance across a room. Begin by having him find an estimated distance without measuring it, by counting how many strides he makes to cover a short distance, then measuring that with a yardstick. The child should then stride across the room, using approximately the same size step, counting as he travels from wall to wall. Have him then calculate the number of strides using division. For example, if it takes two average strides for him to equal one yard, and the distance across the room takes 21 strides, he should estimate the distance across the room to be about 10 1/2 yards. Measuring the distance after the estimation will help him see that using body parts to evaluate sizes is a useful method for arriving at general lengths.
Visual Estimation

Provide a child with a sample of small objects such as buttons that are too large to be counted quickly. Scatter these within a confined area and ask the child to estimate the total number. Teach him to focus on one section of the space and count the smaller number of objects within that area. Then, ask him to visually divide up the larger area into regularsized, smaller chunks and multiply these by the counted number in the smaller area. The product of this would give an estimated number, which should be close to the actual number. Have the child then count the objects to determine his accuracy with this method of estimation.
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