Page 106 - ArithBook5thEd ~ BCC

3.11.2 Exercises

Add or subtract the mixed numbers as indicated. Express the final answers as mixed numbers in proper
form.
1 1
1. 1 +
3 2
2 1 3
2. 3 +7 +1
5 3 5
1
3. 1 +10
5
3 2
4. 75 +91
4 3
11 13
5. 12 − 2
15 20

7 1
6. 3 − 2
8 4
2 4
7. 1 − 1
3 13
3 1 3
8. 3 +1 +
5 2 10
1 3
9. 1 −
7 7
3 3
10. 21 − 19
5 4
6 11
11. 3 −
7 12
11 4
12. 5 − 4
20 5

3.11.3 Measurements in Mixed Units

When a number results from a measurement, it is given in terms of a unit of measure,or unit for short.
For example, if you use a standard ruler to measure the length of a table, the length is given in units of
feet (ft). All 1-foot rulers are divided into 12 smaller units called inches (in), so that

1ft = 12 in.

More precise measurements can be given in terms of the mixed units feet-and-inches. For example,
the length of your table might be 3 feet 6 inches or 3 ft 6 in.
Other familiar examples of mixed units are hours-and-minutes, or hours-minutes-and-seconds. The
abbreviations are hr, min and sec. Of course,

1hr = 60 min and 1 min = 60 sec.

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