Mathematics
Grade 10
15 min
Divide fractions
Divide fractions
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1
Introduction & Learning Objectives
Learning Objectives
Prove the 'invert and multiply' rule for fraction division using algebraic principles.
Divide any combination of proper fractions, improper fractions, and mixed numbers.
Simplify complex fractions involving multiple division operations.
Apply fraction division to solve multi-step word problems involving rates, ratios, and geometric contexts.
Articulate the relationship between division and multiplication by a reciprocal.
Accurately simplify fractions before and after multiplication to find the most reduced final answer.
How many quarters are in six and a half dollars? You just mentally performed fraction division! 🤔
This tutorial revisits the fundamental process of dividing fractions, a critical skill that underpins advanced algebraic manipula...
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Key Concepts & Vocabulary
TermDefinitionExample
Reciprocal (Multiplicative Inverse)The reciprocal of a number is the number you must multiply it by to get 1. For a fraction a/b, the reciprocal is b/a.The reciprocal of 3/7 is 7/3, because (3/7) * (7/3) = 21/21 = 1.
DividendThe number or fraction that is being divided.In the problem 1/2 ÷ 1/4, the dividend is 1/2.
DivisorThe number or fraction by which the dividend is divided.In the problem 1/2 ÷ 1/4, the divisor is 1/4.
Improper FractionA fraction where the numerator (top number) is greater than or equal to the denominator (bottom number).11/4 is an improper fraction. It represents a value greater than 1.
Mixed NumberA number consisting of a whole number and a proper fraction.2 3/4 is a mixed number. It must be converted to an improper fraction (11/4) before perfor...
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Core Formulas
The Fundamental Rule of Fraction Division
\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c} = \frac{ad}{bc}
To divide by a fraction, multiply the dividend (the first fraction) by the reciprocal (multiplicative inverse) of the divisor (the second fraction).
Dividing a Fraction by a Whole Number
\frac{a}{b} \div n = \frac{a}{b} \div \frac{n}{1} = \frac{a}{b} \times \frac{1}{n} = \frac{a}{bn}
First, express the whole number as a fraction with a denominator of 1. Then, apply the fundamental rule of fraction division.
Converting a Mixed Number to an Improper Fraction
A \frac{b}{c} = \frac{(A \times c) + b}{c}
This conversion is a mandatory first step before multiplying or dividing mixed numbers. Multiply the whole number by the denominator and add the numerato...
4 more steps in this tutorial
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Challenging
Which statement provides the most precise algebraic justification for the 'invert and multiply' rule for dividing a/b by c/d?
A.Multiplication is the inverse operation of division.
B.Division is defined as multiplication by the multiplicative inverse (reciprocal).
C.The commutative property of multiplication allows reordering.
D.Any number divided by itself is 1.
Challenging
The area of a triangle is 10 1/8 square units. If its base measures 4 1/2 units, what is its height? (Formula: Area = 1/2 × base × height)
A.2 1/4 units
B.22 19/32 units
C.4 1/2 units
D.9/2 units
Challenging
Let x be a positive fraction where x > 1 (an improper fraction). Let y be a positive fraction where 0 < y < 1 (a proper fraction). Which of the following statements about the quotient q = x ÷ y must be true?
A.q < y
B.y < q < x
C.q = x
D.q > x
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