1. Section 4.1 Study Materials
Introduction to Decimals
Math 081 CCBC

2. Section 4.1 Study Materials
Directions
Please have a piece of paper and pencil ready!
As you click through the slides, pause to work out the Practice Problems on your own.
Check your answer to each Practice Problem.
If you get a problem wrong or if you want to hear the explanation, watch the video linked to the slide.
At the end of the slide show, work out the answers to the Selected Textbook Exercises.
When you have completed Sections 4.1 – 4.3, take the Mid-Chapter 4 Test.

3. Section 4.1 Study Materials
Place Value
Our numbering system is based on powers of 10 and is therefore called the decimal number system, from the Latin root decem, meaning ten. When referring to decimals, we talk about place values just like we do with whole numbers. When we read the number 3,125 we say “three thousand, one hundred twenty-five.” That really means we have 3 thousands, plus 1 hundred, plus 2 tens, plus 5 ones.

4. Section 4.1 Study Materials
Place Value
There are also place values for the numbers to the right of the decimal point as shown in the diagram below : Notice that the values to the right of the decimal point end in ths. Also notice that there is no “oneths” place; the first place to the right of the decimal point is the tenths place. Although they are not listed in the diagram above, after the thousandths place is the ten thousandths place, then the hundred thousandths place, then the millionths place, and so on.

5. Section 4.1 Study Materials

6. Section 4.1 Study Materials
Answers: a. 0 b. 4 c. tens d. ten thousandths Watch it:

7. Section 4.1 Study Materials
Ordering Decimals
Sometimes it is necessary to compare decimal numbers. Note that adding 0 after the rightmost digit does not change the value of the decimal number. As examples, notice:

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Answer: > Watch it:

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12. Section 4.1 Study Materials
Answer: < Watch it:

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Answer: 2.01 pounds Watch it:

15. Section 4.1 Study Materials
Estimating Numbers
Sometimes, we don’t need exact numbers; approximating or estimating is often good enough. If you are at the supermarket and notice that a box of Fructose Flakes cereal costs $4.79, you could estimate its cost to be about $5. Doing so would make it easier to calculate that four boxes will cost you roughly $20. Now, this is not an exact answer, but it’s a pretty close estimate.

16. In this course, we will estimate numbers in the following way:
Section 4.1 Study Materials
In this course, we will estimate numbers in the following way:

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Answer: 1,000 Watch it:

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Answer: 40 Watch it:

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22. Section 4.1 Study Materials
Answer: 0.06 Watch it:

23. Section 4.1 Study Materials
Rounding Decimals

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25. Section 4.1 Study Materials
Answer: Watch it:

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Answer: 12,350 Watch it:

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29. Section 4.1 Study Materials
Answer: Watch it:

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31. Section 4.1 Study Materials
Answer: 8.60 Watch it:

32. Practice Selected Textbook Exercises
Section 4.1 Study Materials
Practice Selected Textbook Exercises
On your own paper, work out the answers to the following problems.
Section 4.1: 1ace, 2cdf, 3ace, 4, 6, 8, 9, 11 – 18
Click here to practice
Selected Textbook Exercises
Section 4.1
This is the end of the Section 4.1 material.
If you got all of the Selected Textbook Exercises for Section 4.1 correct, you are ready for Section 4.2 Study Materials found in Blackboard in Mid-Chapter 4.
If you did not get all of the Selected Textbook Exercises for Section 4.1 correct, continue studying using the additional materials on the next slide.

33. Additional Study Materials:
Section 4.1 Study Materials
Additional Study Materials:
Click here to read the Textbook for Section 4.1.
Click here to re-watch all of the Videos for Section 4.1.
Click here to practice all of the Textbook Exercises for Section 4.1.
Go to Blackboard to view other resources:
Online Exercises for Section 4.1
More videos for Section 4.1
Work on Section 4.1 drill sheets found in the Math 081 file cabinet in the classroom.
Ask your professor or in-class tutor for help.