Ordering Decimals

Lesson Plan - Get It!

Audio:

This is your day!

Decimals are today’s special at the Number Line Diner. But the cook needs help putting the decimal numbers in order from least to greatest.

The cook needs to put these numbers in order: 1.26, 1.8, 1.75, 1.4, 1.82.

Here’s what you can do to help:

Step One Make a table.

Decimal numbers are numbers with a decimal point. The numbers after the decimal point are smaller than 1. We can use a place value table to write decimal numbers. Take a look at the numbers in the place value table:

Step Two Compare the decimal numbers.

1. Begin with the ones place value. All the numbers have a 1 in the ones place, so we move to the first number after the decimal place, or the tenths place value.
2. There are a 2, 8, 7, 4, and 8 in the tenths place. We can place those numbers in order from least to greatest. To find the least, we look for the smallest number first: 2, 4, 7, 8, 8.
3. We are almost done, but there are two 8s in the tenths place. So, we look to the next number, or the hundredths place value.
4. There is a 0 and a 2. We can place those numbers in order from least to greatest: 0, 2.

We can also compare the numbers on the number line. Number lines show sets of numbers in order from least to greatest:

Step Three Order the decimal numbers.

Now that we have compared the numbers, we can place the decimal numbers in order from least to greatest:

1.26, 1.4, 1.75, 1.80, 1.82

Great work!

Make a table on your own sheet of paper and follow the three steps. Place the following decimal numbers in order, this time from greatest to least. Remember, to find the greatest we look for the biggest number first!

6.2, 6.74, 5.3, 6.9, 7.12

• Does your answer look like this? 7.12, 6.9, 6.74, 6.2, 5.3

Fantastic! If you made a mistake, read through the steps again.

• Where did you go wrong?

Hints

1. Greatest to least looks for the biggest number to the smallest number.
2. 7.12 comes first because there is a 7 in the ones place. 5.3 comes last because there is a 5 in the ones place.
3. To order the middle numbers, you can look at the tenths place. 9 is greater than 7. 7 is greater than 2.

Placing decimal numbers in order is like ordering any whole number until you get to the decimal point. Then, you just compare the numbers from the first number after the decimal point to the last number. Remember when you are comparing and ordering numbers to keep the decimal point in the right place. It is important to compare the same place value in two or more numbers.

Now, try some games and puzzles to practice ordering decimal numbers in the Got It? section.