∑ Old Books, New Math

Chapter 16 · Fractions

Chapter challenge

Ten problems drawn from every lesson in the chapter. Get each one right on your first try for a perfect score. A new set is drawn each time.

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From Adding Fractions: Watch the Signs, exercise 58

Products of factors in the denominators.

1

\displaystyle \frac{3a}{(a-3)(a-4)}-\frac{2a}{(3-a)(4-a)}

From Complex Fractions, exercise 16

Now with letters. Give a single fraction in lowest terms.

2

\displaystyle \frac{\frac{m^3}{n^3}+1}{m+\frac{n^2}{m}-n}

From Mixed Expressions, exercise 12

Reduce each fraction to a mixed expression: a whole part plus (or minus) a fraction. Type it like 3x - 2 + 2/(5x).

3

\dfrac{x^6+y^6}{x^2-y^2}

From Multiplying Fractions, exercise 22

Mixed and whole expressions: turn them into fractions first, as in Example 3.

4

\displaystyle \frac{x^3-8}{6xy}\cdot\left(3-\frac{4}{2-x}\right)\cdot\frac{18x^2y^2}{x^2+2x+4}

From Dividing Fractions, exercise 7

Perform the indicated operations. Work from left to right: invert each divisor, then multiply.

5

\displaystyle \frac{6}{(2x)^2}\div\frac{12}{(4x^2)^3}\cdot\left(\frac{2}{x}\right)^2

From Equivalent Fractions and the L.C.D., exercise 2

Change each set of fractions to equivalent fractions with the lowest common denominator. You may type the denominator factored, like (5x+1)/(6(x+1)).

6

\dfrac{5}{24} and \dfrac{7}{32}

From Adding and Subtracting Fractions, exercise 31

Whole expressions mixed with fractions: write the whole part over 1, as in Example 3.

7

\displaystyle R^2+\frac{R^2}{4}

From Complex Fractions, exercise 19

Now with letters. Give a single fraction in lowest terms.

8

\displaystyle \frac{1+\frac{b}{a}-\frac{20a}{b}}{\frac{b}{a}-\frac{8a}{b}-2}

From Changes of Sign in a Fraction, exercise 7

Write each fraction in three other ways. The sign in front of the fraction is shown; type the fraction that comes after it, like x/(-y) or (-x + 3)/(2x + 4).

9

\dfrac{x^2-5x+6}{x^2-7x+12}

From Reducing Fractions to Lowest Terms, exercise 9

Reduce each fraction to lowest terms. Type answers like (x + 1)/(x - 2).

10

\displaystyle \frac{a^2-1}{a^2-2a+1}