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.