Algebra Demystified 2nd Ed

12 alGebra De mystif ieD

SOLUTIONS

1.^600
1280

10 60

10 128

60

128

415

432

15

32

= ⋅

⋅

==⋅

⋅

=

2.^68
578

234

2289

34

289

172

17 17

2

17

= ⋅

⋅

==⋅

⋅

=

3.^168
216

628

636

28

36

47

49

7

9

= ⋅

⋅

==⋅

⋅

=

4.^72
120

12 6

12 10

6

10

23

25

3

5

= ⋅

⋅

==⋅

⋅

=

5.^768
288

4 192

472

192

72

296

236

96

36

424

49

= ⋅^24

⋅

==⋅

⋅

==⋅

⋅

=

99

38

33

8

3

= ⋅

⋅

=

For the rest of the book, we will write fractions in lowest terms.

Adding and Subtracting Fractions with Like Denominators

If we want to add or subtract two fractions having the

same denominators, we only need to add or subtract their

numerators. The rule is ab+=cb acb+ and ab−=bc acb−.

Let us examine the sum^16 +^26 with a pie chart.

Adding 1 one-sixth segment to 2 one-sixth segment

gives us a total of 3 one-six segments, which agrees with

the formula: 61 += 62 12 + 6 == 63 21.

EXAMPLES

Perform the addition or subtraction.

7

9

2

9

72

9

5

9

−=− =

8

15

2

15

82

15

10

15

52

53

2

3

+=+ ==⋅

⋅

=

PRACTICE

Perform the addition or subtraction.

1.^47 −=^17
2.^1
5

3

5

+=

1

6

1

(^1 6)
6
FIGURE 1-7
✔SOLUTIONS
EXAMPLES
Perform the addition or subtraction.
PRACTICE
Perform the addition or subtraction.