Make one column on a white board with a dry erase marker to introduce children to the concept of units, tenths and hundredths. Write "Units" at the top of the column and place between one and nine dots inside the column. Write the number of dots beneath the column head. Draw another column to the left of the first one and label it "Tenths." Draw ten dots in the column and write "1" at the top, beneath the column head. Help the children understand that you have just made a visual representation of a number between 11 and 19. Fill the columns with different dots helping the children understand the concept of the tenth place in numbers.
Draw a third column to the left of the existing two and label it "Hundredths." Fill it with 100 dots. Place no dots in the "Tenths" and "Units" columns to represent the number "100." Fill the three columns with different numbers of dots to represent different numbers and help children understand the hundredth and tenth places in numbers.
Erase all columns and draw a large square on the board. Instruct the children to think of the square as one unit. Divide the square into 10 sections and ask the children what portion of the square each section is worth or represents. Help them understand that the answer is "tenths." Divide each of the 10 sections further into 10 squares and explain that there are now 100 sections within the unit. Ask the children what this number place is called and expect the answer "hundredths" from the children.
Explain the decimal point and what it is used for after children understand the concept of number place and the related concepts of hundredths and tenths. Draw a four column chart on the board with three or more rows in it. Write "Units," "Decimal Point," "Tenths" and "Hundredths" across the top row in the columns from left to right. Write numbers like "3.74" or "2.98" in the rows beneath from left to right.
Help children read the numbers and identify which number is the "tenth" and which is the "hundredth." Erase the chart and give each child a piece of paper with 10 numbers on it, each one following the format of "#.##" and ask the students to label which part of each number is the tenth and which is the hundredth.