multiplying fractions with whole numbers
Multiplying a fraction by a whole number means taking that fraction repeatedly a certain number of times. For example, 14×3\frac{1}{4}\times 341×3 means “3 groups of one‑quarter.”
Quick Scoop
- Turn the whole number into a fraction (put it over 1).
- Multiply the top numbers (numerators).
- Multiply the bottom numbers (denominators).
- Simplify the fraction if possible.
Step‑by‑Step Method
- Rewrite the whole number as a fraction
- Example: 5=515=\frac{5}{1}5=15.
- Multiply the numerators (top numbers)
- Example: 23×5=23×51⇒2×5=10\frac{2}{3}\times 5=\frac{2}{3}\times \frac{5}{1}\Rightarrow 2\times 5=1032×5=32×15⇒2×5=10.
- Multiply the denominators (bottom numbers)
- Using the same example: 3×1=33\times 1=33×1=3, so you get 103\frac{10}{3}310.
- Simplify or turn into a mixed number if needed
- 103=313\frac{10}{3}=3\frac{1}{3}310=331.
Worked Examples
Think of it as “repeated addition,” but much quicker.
Example 1: 18×5\frac{1}{8}\times 581×5
- Step 1: 5=515=\frac{5}{1}5=15.
- Step 2: Multiply numerators: 1×5=51\times 5=51×5=5.
- Step 3: Multiply denominators: 8×1=88\times 1=88×1=8.
- Answer: 58\frac{5}{8}85.
Example 2: 34×4\frac{3}{4}\times 443×4
- Step 1: 4=414=\frac{4}{1}4=14.
- Step 2: Numerators: 3×4=123\times 4=123×4=12.
- Step 3: Denominators: 4×1=44\times 1=44×1=4.
- Step 4: 124=3\frac{12}{4}=3412=3.
Visual / Real‑Life Picture
- 13×15\frac{1}{3}\times 1531×15 can be seen as “one‑third of 15.”
- You can imagine 15 objects split equally into 3 groups; each group has 5, so 13×15=5\frac{1}{3}\times 15=531×15=5.
Tiny Story to Remember It
Imagine you have a recipe that uses 25\frac{2}{5}52 of a cup of sugar for one batch of cookies, and you want to bake 3 batches.
- You are really doing 25×3\frac{2}{5}\times 352×3: three groups of 25\frac{2}{5}52.
- Convert 3 to a fraction: 31\frac{3}{1}13.
- Multiply: 25×31=65=115\frac{2}{5}\times \frac{3}{1}=\frac{6}{5}=1\frac{1}{5}52×13=56=151 cups of sugar total.
Quick HTML Table: Examples
html
<table>
<tr>
<th>Expression</th>
<th>Step Form</th>
<th>Answer</th>
</tr>
<tr>
<td>1/8 × 5</td>
<td>(1/8) × (5/1)</td>
<td>5/8</td>
</tr>
<tr>
<td>3/4 × 4</td>
<td>(3/4) × (4/1)</td>
<td>3</td>
</tr>
<tr>
<td>2/5 × 3</td>
<td>(2/5) × (3/1)</td>
<td>6/5 = 1 1/5</td>
</tr>
</table>
Tiny TL;DR
To multiply fractions with whole numbers, write the whole number over 1, multiply tops, multiply bottoms, then simplify.
Information gathered from public forums or data available on the internet and portrayed here.