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Representing, Comparing,
3-1 and Ordering Decimals
I CAN write decimals in standard form,
expanded form, and words.
I CAN compare two decimals.
I CAN order three or more decimals.
Representing, Comparing,
3-1 and Ordering Decimals
Place value can help you understand and
write and compare decimal numbers.
Representing, Comparing,
3-1 and Ordering Decimals
Example 1: Reading and Writing Decimals
Write each decimal in standard form, expanded
form, and words.
A. 1.07
Expanded form: 1 + 0.07
Word form: one and seven hundredths
B. 0.03 + 0.006 + 0.0009
Standard form: 0.0369
Word form: three hundred sixty-nine ten-thousandths
Representing, Comparing,
3-1 and Ordering Decimals
Example 1: Reading and Writing Decimals
Write the decimal in standard form and
expanded form.
C. fourteen and eight hundredths
Standard form:
14.08
Expanded form:
10 + 4 + 0.08
Representing, Comparing,
3-1 and Ordering Decimals
You Try! Example 1
Write each decimal in standard form, expanded
form, and words.
A. 1.12
Expanded form: 1 + 0.1 + 0.02
Word form: one and twelve hundredths
B. 0.6 + 0.008 + 0.0007
Standard form: 0.6087
Word form: six thousand eighty-seven ten-thousandths
Representing, Comparing,
3-1 and Ordering Decimals
You Try! Example 1
Write each decimal in standard form and
expanded form.
C. eleven and two hundredths
Standard form: 11.02
Expanded form: 10 + 1 + 0.02
Representing, Comparing,
3-1 and Ordering Decimals
Example 2: Earth Science Application
The star Wolf 359 has an apparent magnitude
of 13.5. Suppose another star has an apparent
magnitude of 13.05. Which star has the smaller
magnitude?
13.50
Line up the decimal points.
Start from the left and compare the digits.
13.05
Look for the first place where the digits are
different.
0 < 5.
13.05 < 13.50
The star that has an apparent magnitude of 13.05
has the smaller magnitude.
Representing, Comparing,
3-1 and Ordering Decimals
You Try! Example 2
Tina reported on a star for her science project
that has a magnitude of 11.3. Maven reported
on another star that has a magnitude of 11.28.
Which star has the smaller magnitude?
11.30
Line up the decimal points.
Start from the left and compare the digits.
11.28
Look for the first place where the digits are
different.
2 is less than 3.
11.28 < 11.30
The star that has a magnitude of 11.28 has the
smaller magnitude.
Representing, Comparing,
3-1 and Ordering Decimals
Example 3: Ordering Decimals
Order the decimals from least to greatest.
16.67, 16.6, 16.07
16.67
16.60
16.07
16.67
16.60
16.07
Rewrite the numbers so they have
the same number of decimal
place values.
Start at the left and compare the
digits.
Look for the first place where the
digits are different.
The numbers in order from least to greatest are 16.07, 16.6, 16.67
Representing, Comparing,
3-1 and Ordering Decimals
You Try! Example 3
Order the decimals from least to greatest.
12.042, 12.4, 12.02
12.02, 12.042, 12.4
Representing, Comparing,
3-1 and Ordering Decimals
CAN YOU write decimals in standard form,
expanded form, and words?
CAN YOU compare two decimals?
CAN YOU order three or more decimals?
Representing, Comparing,
3-1 and Ordering Decimals
Lesson Quiz
Write each in standard form, expanded form
and words.
1. 8.0342
8 + 0.03 + 0.004 + 0.0002; eight and
three hundred forty-two ten thousandths
2. 10 + 8 + 0.3 + 0.006
18.306; eighteen and three hundred six thousandths
3. eight and twelve hundredths
8.12; 8 + 0.1 + 0.02
Representing, Comparing,
3-1 and Ordering Decimals
Lesson Quiz: Part II
4. It takes Pluto 246.7 years to orbit the Sun, and it
takes Neptune 164.8 years. Which takes longer to
orbit the Sun?
Pluto
5. Order the decimals from least to greatest: 16.35,
16.3, 16.5.
16.3, 16.35, 16.5
Representing, Comparing,
3-1 and Ordering Decimals
HOMEWORK