Math 204 · Section 6.3 · Santa Ana College

Multiplication & Division of Fractions

Interactive Visual Explorer · Dr. Romero

SLO 6.3 · Conceptual Foundation

Conceptual understanding must come first. Students need to see why it makes sense before executing procedures. Explore the three cases your textbook identifies, then see the visual area model that makes fraction × fraction visible.

Three Cases of Fraction Multiplication
REPEATED ADDITION
Case 1: Whole Number × Fraction

When the first factor is a whole number, we can use repeated addition — the familiar extension of whole-number multiplication. 3 × ¼ means add ¼ three times.

Whole number
×
Fraction
📐 The Rule — Built from Understanding

Once you've seen why it works through the area model, the rule is simply:
a/b × c/d = ac/bd  — multiply numerators, multiply denominators, then simplify.

Conceptual Foundation First

Before any procedure, students must understand: a ÷ b asks "how many groups of b fit into a?" The fraction tile model makes this visible — line up divisor tiles under the dividend and count how many fit. Work through the three examples below. Press Show Groups on each to see the answer revealed.

📖 How to Read the Tile Model
1/2
Dividend row
All bars = same width (1 whole). Colored tiles show your fraction. Each tile is labeled with its unit fraction.
1 group row
Shows what one divisor-group looks like. Different tile widths = different fraction sizes.
Groups bar
Each color = one group of the divisor placed consecutively. Dashed green line = end of dividend.
EXAMPLE 1 · Exact Groups
½ ÷ ⅙

🍕 You have ½ of a pizza. Each slice is ⅙ of the whole pizza. How many slices do you have?

EXAMPLE 2 · Same Denominator
¾ ÷ ¼

🧁 You have ¾ cup of sugar. Each batch of cookies needs ¼ cup. How many batches can you make?

EXAMPLE 3 · Partial Group
⅔ ÷ ½

🚶 Rosa's school is ⅔ of a mile away. She walks in segments of ½ mile before resting. How many full segments does she walk — and how far through the last segment does she get?

Note: The answer 1⅓ means she completes 1 full half-mile segment and then walks ⅓ of a second segment (i.e., ⅓ × ½ = ⅙ of a mile further). Distance is continuous — a partial segment makes sense here!

💡 The Big Idea
When the divisor is smaller than the dividend
More than one group fits → quotient > 1
Example: ½ ÷ ⅙ = 3
When the divisor is larger than the dividend
Less than one group fits → quotient < 1
Example: ¼ ÷ ½ = ½
⚠️ Context matters for partial groups! A fractional quotient only makes real-world sense when the quantity is continuous (distance, liquid, time, fabric length). Avoid contexts like "how many bows can you make?" — you can't make ⅓ of a bow! Choose contexts where being partway through a group is meaningful.
Four Methods from Your Textbook

Your book presents four ways to divide fractions. Invert & Multiply is the standard, but the others reveal deep conceptual connections. Use whichever method fits the problem — some are faster for special cases!

Division Method Explorer
Dividend
÷
Divisor
Step 0
When to Use Each Method
Invert & Multiply
Works for any fraction division. Most widely applicable. The standard algorithm.
Common Denominator
Best when fractions already share a denominator. Simply divide the numerators!
Missing Factor
Turns division into multiplication. Great for building conceptual understanding.
Divide Across
Divide numerator by numerator, denominator by denominator. Works when they divide evenly!
Practice Score
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Practice Problem
Compute
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