1. 3-1 Representing, Comparing, and Ordering Decimals Warm Up
Problem of the Day
Lesson Presentation
Course 1

2. Warm Up
Order the numbers from least to greatest.
1. 242, 156, 224, 165
2. 941, 148, 914, 814, 721
3. 345, 376, 354, 397
156, 165, 224, 242
148, 721, 814, 914, 941
345, 354, 376, 397

3. Problem of the Day
Lupe is taller than Reba and shorter than Miguel. Tory is shorter than Lupe but taller than Reba. List the four brothers and sisters in order from tallest to shortest.
Miguel, Lupe, Tory, Reba

4. Learn to write, compare, and order decimals using place value and number lines.

5. Additional Example 1: Reading and Writing Decimals
Write each decimal in standard form, expanded form, and words.
A. 1.07 B
Expanded form:
Word form:
one and seven hundredths
Standard form:
0.0369
Word form:
three hundred sixty-nine ten-thousandths

6. Additional 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:

7. Check It Out: Example 1
Write each decimal in standard form, expanded form, and words.
A. 1.12 B
Expanded form:
Word form:
one and twelve hundredths
Standard form:
0.6087
Word form:
six thousand eighty-seven ten-thousandths

8. Check It Out: Example 1
Write each decimal in standard form and expanded form.
C. eleven and two hundredths
Standard form:
11.02
Expanded form:

9. Additional Example 2: Earth Science Application
The star Wolf 359 has an apparent magnitude of Suppose another star has an apparent magnitude of Which star has the smaller magnitude?
Line up the decimal points.
Start from the left and compare the digits.
13.50
Look for the first place where the digits are different.
13.05
0 is less than 5.
13.05 < 13.50
The star that has an apparent magnitude of has the smaller magnitude.

10. Check It Out: Example 2
Tina reported on a star for her science project that has a magnitude of Maven reported on another star that has a magnitude of Which star has the smaller magnitude?
Line up the decimal points.
Start from the left and compare the digits.
11.30
Look for the first place where the digits are different.
11.03
0 is less than 3.
11.03 < 11.30
The star that has a magnitude of has the smaller magnitude.

11. Order the decimals from least to greatest.
Additional Example 3: Comparing and Ordering Decimals
Order the decimals from least to greatest.
16.67, 16.6, 16.07
Compare two of the numbers at a time.
Write 16.6 as “16.60.”
16.67
16.60
16.60 < 16.67
16.67
16.07
Start at the left and compare the digits.
16.07 < 16.67
16.60
16.07
Look for the first place where the digits are different.
16.07 < 16.60

12. Additional Example 3 Continued
Graph the numbers on a number line.
16.6
16.67
16.07
The numbers are ordered when you read the number line from left to right. The numbers in order from least to greatest are 16.07, 16.6, and

13. Order the decimals from least to greatest.
Check It Out: Example 3
Order the decimals from least to greatest.
12.42, 12.4, 12.02
Compare two of the numbers at a time.
Write 12.4 as “12.40.”
12.42
12.40
12.40 < 12.42
12.42
12.02
Start at the left and compare the digits.
12.02 < 12.42
12.40
12.02
Look for the first place where the digits are different.
12.02 < 12.40

14. Check It Out: Example 3 Continued
Graph the numbers on a number line.
12.42
12.4
12.02
The numbers are ordered when you read the number line from left to right. The numbers in order from least to greatest are 12.02, 12.4, and

15. Lesson Quiz: Part I
Write each in standard form, expanded form and words.
3. eight and twelve hundredths
; eight and three hundred forty-two ten thousandths
18.306; eighteen and three hundred six thousandths
8.12;

16. Lesson Quiz: Part II
4. It takes Pluto years to orbit the Sun, and it takes Neptune years. Which planet takes longer to orbit the Sun?
5. Order the decimals from least to greatest: 16.35, 16.3, 16.5.
Pluto
16.3, 16.35, 16.5