To put decimal numbers in order:

First look at the whole number (to the left of the
decimal point).  If that number is different we just
follow our rules for ordering whole numbers.

If the whole number is the same, we then look to the digits to the right
of the decimal point.

Take one place at a time (beginning with the tenth place) until the
digits are different.  We would then compare those digits to put the
numbers in order.

Example 1:

Put in order from least to greatest:

12.871          12.781          12.71         12.178

Solution:

We can see that to the right of the decimal point the whole number is
a "12" for all four decimal numbers.

We then look to the tenths place of each number and we can see
that the fourth number has a "1" in the tenth place.  Therefore
12.178 is the smallest number of the set.

The second and third numbers have a "7" in the tenth place.  We
look then to the hundredth place and see the second number
contains an "8" and the third number contains a "1" in the
hundredth place.  Therefore 12.71 is the next smallest number
followed by 12.781.

The only remaining decimal number is 12.871, which is the largest of
the four.

The numbers ordered least to greatest:

12.178       12.71        12.781        12.871

Example 2:

Put in order from greatest to least:

4.09        3.9        4.19        3.19        3.09

Solution:

We first look at the whole number and see that "4" is greater than
"3" so we will first compare 4.09 and 4.19.

In the tenth place we see a "0" and a "1".  Since "1" is greater than
"0", 4.19 is greater than 4.09.

Next we will compare the numbers remaining.  In the tenth place are
a "9", a "1" and a "0".  We will order them as such (greatest to
least).

The numbers ordered greatest to least:

4.19        4.09        3.9        3.19        3.09

Remember, to put decimal numbers in order:

First look at the whole number

If the whole number is different, use them to order the decimal numbers

If the whole numbers are the same, start ordering the decimal numbers beginning with the tenth place and moving to the right until you find the digits that are different.

Also, always remember to READ carefully to see if you are ordering least to greatest or greatest to least!

Let's Practice

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