Lesson Plans on Comparing Decimals

Teaching Strategies for Comparing Decimals

Place Values

By the time students begin learning decimals, commonly in fourth grade, they should have a good understanding of the place values in whole numbers. These values for a large number - beginning at the right and moving left - are units, tens, hundreds, thousands, ten thousands and so on. One of the first things they learn about decimals is that they also have place values.

Decimal place values are the mirror image of whole-number place values, with -ths added to the names. In other words, you start at the left and move to the right. Keeping with the mirror image analogy, you may want to liken the decimal point to the units place. Then, there are the tenths, hundredths, thousandths, ten thousandths, etc. To begin comparing decimals, students need to have this concept mastered.

Lesson Plan

Generate Interest

Review place values with The Place Value Rap by Tim Bedley and Ben Jacobs. Print out lyrics or have the students make up their own mnemonics for remembering the place values.

Presentation

Model the steps by completing them on the board. Be sure to explain what you are doing aloud to help the students follow along.

Draw a chart. Label the top row with the place value names for decimals. Put decimal numbers in the next two rows, such as .135 and .041.

Begin in the tenths column. If one number is larger than the other (1 in .135 is larger than 0 in .041), then that decimal is larger than the other, no matter what other numbers appear to the right.

If the two numbers are that same, as in .641 and .639, move to the hundredths column. Here, you would see that 4 in .641 is larger than 3 in .639. You can stop there, because this shows that .641 is larger than .639.

If the numbers are the same, as in .012 and .013, move to the next column and repeat the procedure as often as necessary.

Guided Practice

Worksheets are an obvious possibility for giving students a chance to practice what they learned. However, students might be more engaged if you reinforce the material with a game instead. For instance, give each student a card with a decimal number written on it. Instruct them to put themselves in order without speaking.

Alternatively, make a large number line and have your students put decimals numbers in numerical order. Visualizing decimals on a number line will especially help your visual learners.

Closure

Closure is sometimes done through classroom discussion, with the teacher asking questions to stimulate the discussion. Students are given the opportunity to say what they learned during the lesson, what questions they still have about the topic and how the new material fits in with what they have already learned. This activity not only helps the student, but gives the teacher insight into how the students learn and what can be done differently in later classes.