We can show this with pizzas, too. Figure 4.4(a) shows a single pizza, cut into two equal pieces with
These models lead to the Equivalent Fractions Property, which states that if we multiply the numerator and denominator of a fraction by the same number, the value of the fraction does not change.
When working with fractions, it is often necessary to express the same fraction in different forms. To find equivalent forms of a fraction, we can use the Equivalent Fractions Property. For example, consider the fraction one-half.
Locate Fractions and Mixed Numbers on the Number Line
Now we are ready to plot fractions on a number line. This will help us visualize fractions and understand their values.
Doing the Manipulative Mathematics activity "Number Line Part 33" will help you develop a better understanding of the location of fractions on the number line.
Let us locate 15,45,3,313,74,92,5,15,45,3,313,74,92,5, and 8383 on the number line.
We will start with the whole numbers 33 and 55 because they are the easiest to plot.
The proper fractions listed are 1515 and 45.45. We know proper fractions have values less than one, so 1515 and 4545 are located between the whole numbers 00 and 1.1. The denominators are both 5,5, so we need to divide the segment of the number line between 00 and 11 into five equal parts. We can do this by drawing four equally spaced marks on the number line, which we can then label as 15,25,35,15,25,35, and 45.45.
Now plot points at 1515 and 45.45.
The only mixed number to plot is 313.313. Between what two whole numbers is 313?313? Remember that a mixed number is a whole number plus a proper fraction, so 313>3.313>3. Since it is greater than 3,3, but not a whole unit greater, 313313 is between 33 and 4.4. We need to divide the portion of the number line between 33 and 44 into three equal pieces (thirds) and plot 313313 at the first mark.
Finally, look at the improper fractions 74,92,74,92, and 83.83. Locating these points will be easier if you change each of them to a mixed number.
74=134,92=412,83=22374=134,92=412,83=223
Here is the number line with all the points plotted.
Locate and label the following on a number line: 34,43,53,415,34,43,53,415, and 72.72.
- Answer
Start by locating the proper fraction 34.34. It is between 00 and 1.1. To do this, divide the distance between 00 and 11 into four equal parts. Then plot 34.34.
Next, locate the mixed number 415.415. It is between 44 and 55 on the number line. Divide the number line between 44 and 55 into five equal parts, and then plot 415415 one-fifth of the way between 44 and 55.
Now locate the improper fractions 4343 and 5353.
It is easier to plot them if we convert them to mixed numbers first.
4 3 = 1 1 3 , 5 3 = 1 2 3 4 3 = 1 1 3 , 5 3 = 1 2 3
Divide the distance between 11 and 22 into thirds.
Next let us plot 72.72. We write it as a mixed number, 72=31272=312. Plot it between 33 and 4.4.
The number line shows all the numbers located on the number line.
Locate and label the following on a number line: 13,54,74,235,92.13,54,74,235,92.
Locate and label the following on a number line: 23,52,94,114,325.23,52,94,114,325.
In Introduction to Integers, we defined the opposite of a number. It is the number that is the same distance from zero on the number line but on the opposite side of zero. We saw, for example, that the opposite of 77 is −7−7 and the opposite of −7−7 is 7.7.
Fractions have opposites, too. The opposite of 3434 is −34.−34. It is the same distance from 00 on the number line, but on the opposite side of 0.0.
Thinking of negative fractions as the opposite of positive fractions will help us locate them on the number line. To locate −158−158 on the number line, first think of where 158158 is located. It is an improper fraction, so we first convert it to the mixed number 178178 and see that it will be between 11 and 22 on the number line. So its opposite, −158,−158, will be between −1−1 and −2−2 on the number line.
Locate and label the following on the number line: 14,−14,113,−113,52,14,−14,113,−113,52, and −52.−52.
- Answer
Draw a number line. Mark 00 in the middle and then mark several units to the left and right.
To locate 14,14, divide the interval between 00 and 11 into four equal parts. Each part represents one-quarter of the distance. So plot 1414 at the first mark.
To locate −14,−14, divide the interval between 00 and −1−1 into four equal parts. Plot −14−14 at the first mark to the left of 0.0.
Since 113113 is between 11 and 2,2, divide the interval between 11 and 22 into three equal parts. Plot 113113 at the first mark to the right of 1.1. Then since −113−113 is the opposite of 113113 it is between −1−1 and −2.−2. Divide the interval between −1−1 and −2−2 into three equal parts. Plot −113−113 at the first mark to the left of −1.−1.
To locate 5252 and −52,−52, it may be helpful to rewrite them as the mixed numbers 212212 and −212.−212.
Since 212212 is between 22 and 3,3, divide the interval between 22 and 33 into two equal parts. Plot 5252 at the mark. Then since −212−212 is between −2−2 and −3,−3, divide the interval between −2−2 and −3−3 into two equal parts. Plot −52−52 at the mark.
Locate and label each of the given fractions on a number line:
23,−23,214,−214,32,−3223,−23,214,−214,32,−32
Locate and label each of the given fractions on a number line:
34,−34,112,−112,73,−7334,−34,112,−112,73,−73
Order Fractions and Mixed Numbers
We can use the inequality symbols to order fractions. Remember that a>ba>b means that aa is to the right of bb on the number line. As we move from left to right on a number line, the values increase.
Order each of the following pairs of numbers, using << or >:>:
- ⓐ−23____−1−23____−1
- ⓑ−312____−3−312____−3
- ⓒ−37____−38−37____−38
- ⓓ−2____−169−2____−169
- Answer
ⓐ −23>−1−23>−1
ⓑ −312<−3−312<−3
ⓒ −37<−38−37<−38
ⓓ −2<−169−2<−169
Order each of the following pairs of numbers, using << or >:>:
- ⓐ−13__−1−13__−1
- ⓑ−112__−2−112__−2
- ⓒ−23__−13−23__−13
- ⓓ−3__−73−3__−73
Order each of the following pairs of numbers, using << or >:>:
- ⓐ−3__−175−3__−175
- ⓑ−214__−2−214__−2
- ⓒ−35__−45−35__−45
- ⓓ−4__−103−4__−103
ACCESS ADDITIONAL ONLINE RESOURCES
Section 4.1 Exercises
Practice Makes Perfect
In the following exercises, name the fraction of each figure that is shaded.
In the following exercises, shade parts of circles or squares to model the following fractions.
In the following exercises, use fraction circles to make wholes using the following pieces.
In the following exercises, name the improper fractions. Then write each improper fraction as a mixed number.
In the following exercises, draw fraction circles to model the given fraction.
In the following exercises, rewrite the improper fraction as a mixed number.
In the following exercises, rewrite the mixed number as an improper fraction.
In the following exercises, use fraction tiles or draw a figure to find equivalent fractions.
44.
How many sixths equal one-third?
45.
How many twelfths equal one-third?
46.
How many eighths equal three-fourths?
47.
How many twelfths equal three-fourths?
48.
How many fourths equal three-halves?
49.
How many sixths equal three-halves?
In the following exercises, find three fractions equivalent to the given fraction. Show your work, using figures or algebra.
In the following exercises, plot the numbers on a number line.
56.
2 3 , 5 4 , 12 5 2 3 , 5 4 , 12 5
57.
1 3 , 7 4 , 13 5 1 3 , 7 4 , 13 5
58.
1 4 , 9 5 , 11 3 1 4 , 9 5 , 11 3
59.
7 10 , 5 2 , 13 8 , 3 7 10 , 5 2 , 13 8 , 3
60.
2 1 3 , −2 1 3 2 1 3 , −2 1 3
61.
1 3 4 , −1 3 5 1 3 4 , −1 3 5
62.
3 4 , − 3 4 , 1 2 3 , −1 2 3 , 5 2 , − 5 2 3 4 , − 3 4 , 1 2 3 , −1 2 3 , 5 2 , − 5 2
63.
2 5 , − 2 5 , 1 3 4 , −1 3 4 , 8 3 , − 8 3 2 5 , − 2 5 , 1 3 4 , −1 3 4 , 8 3 , − 8 3
In the following exercises, order each of the following pairs of numbers, using << or >.>.
64.
−1 __ − 1 4 −1 __ − 1 4
65.
−1 __ − 1 3 −1 __ − 1 3
66.
−2 1 2 __ − 3 −2 1 2 __ − 3
67.
−1 3 4 __ − 2 −1 3 4 __ − 2
68.
− 5 12 __ − 7 12 − 5 12 __ − 7 12
69.
− 9 10 __ − 3 10 − 9 10 __ − 3 10
70.
−3 __ − 13 5 −3 __ − 13 5
71.
−4 __ − 23 6 −4 __ − 23 6
Everyday Math
72.
Music Measures A choreographed dance is broken into counts. A 1111 count has one step in a count, a 1212 count has two steps in a count and a 1313 count has three steps in a count. How many steps would be in a 1515 count? What type of count has four steps in it?
73.
Music Measures Fractions are used often in music. In 4444 time, there are four quarter notes in one measure.
- ⓐ How many measures would eight quarter notes make?
- ⓑ The song “Happy Birthday to You” has 2525 quarter notes. How many measures are there in “Happy Birthday to You?”
74.
Baking Nina is making five pans of fudge to serve after a music recital. For each pan, she needs 1212 cup of walnuts.
- ⓐ How many cups of walnuts does she need for five pans of fudge?
- ⓑ Do you think it is easier to measure this amount when you use an improper fraction or a mixed number? Why?
Writing Exercises
75.
Give an example from your life experience (outside of school) where it was important to understand fractions.
76.
Explain how you locate the improper fraction 214214 on a number line on which only the whole numbers from 00 through 1010 are marked.
Self Check
ⓐ After completing the exercises, use this checklist to evaluate your mastery of the objectives of this section.
ⓑ If most of your checks were:
…confidently. Congratulations! You have achieved the objectives in this section. Reflect on the study skills you used so that you can continue to use them. What did you do to become confident of your ability to do these things? Be specific.
…with some help. This must be addressed quickly because topics you do not master become potholes in your road to success. In math, every topic builds upon previous work. It is important to make sure you have a strong foundation before you move on. Whom can you ask for help? Your fellow classmates and instructor are good resources. Is there a place on campus where math tutors are available? Can your study skills be improved?
…no—I don’t get it! This is a warning sign and you must not ignore it. You should get help right away or you will quickly be overwhelmed. See your instructor as soon as you can to discuss your situation. Together you can come up with a plan to get you the help you need.