Using A Round-O-Meter To Estimate

Kathleen M.K. Pidrak Edward H. White
1137 W. 122 St.
Chicago IL 60643
(312) 535-5672

Objectives: The student will demonstrate knowledge of rounding numbers to the nearest dollar or nearest dime. Materials needed: scissors string tape pencil Round-O-Meter worksheet Round It Game overhead Overhead School Store paper base ten blocks graph for base ten blocks Strategy: 1. Introduce several items that students would need to purchase for school. Write the items and their cost on the board. Talk about how we need to round to get an idea of how much money we need. 2. Using paper copies of the base ten blocks on a graph show if a number falls above or below the half mark. If we are closer to the first number we round down, if we are closer to the second number we round up. For our lesson we will let 1 flat represent a dollar, one rod represent a dime and one unit represent a penny. Demonstrate several of the items that the students mentioned. Pass out individual pieces of the base ten papers and a graph so the students can try this for themselves. 3. A Round-O-Meter is an instrument that we will make to show us which direction to round. The Round-O-Meter is a piece of paper about the size of a ruler. Attach a piece of string to the center of the Round-O-Meter, one end is folded into an arrow. Write the numbers 1, 2, 3, 4, 0 on the end of the strip with the arrow. Write the numbers 5, 6, 7, 8, 9, on the other end of the paper. When you hold the Round-O-Meter by the string and put a paper clip on the number you are looking at, the arrow will go up or down. This will show the children which direction to round. 4. After the children use their Round-O-Meter several times to prove to themselves that it will work there is a follow up worksheet that they can use to reinforce their new skill. Conclusions: Showing the children that one number is closer to another is very beneficial in that they can easily figure which direction to round. The Round- O-Meter serves as a reminder and is something that they can keep at their desk.
Return to Mathematics Index