## What Is Division of Fractions?
To **divide fractions**, you use the "invert and multiply" rule:
$\frac{a}{b} \div \frac{c}{d} = \frac{a}{b} \times \frac{d}{c}$
In other words, flip the second fraction and then multiply.
Division is just multiplication by the reciprocal.
## Step-by-Step: How to Divide Fractions
Example:
$\frac{3}{4} \div \frac{2}{5}$
### Step 1: Flip the second fraction
$\frac{2}{5} \; \rightarrow \; \frac{5}{2}$
### Step 2: Multiply
$\frac{3}{4} \times \frac{5}{2} = \frac{15}{8}$
### Step 3: Convert to a mixed number if needed
$\frac{15}{8} = 1 \tfrac{7}{8}$
**Final Answer:**
$\frac{3}{4} \div \frac{2}{5} = \frac{15}{8}$
## Real-World Example: Current Division
In a parallel circuit, current divides based on resistance. The formula is:
$I_1 = I_T \times \frac{R_T}{R_1}$
Suppose:
- $I_T = 6 \, A$
- $R_T = \tfrac{3}{4} \, \Omega$
- $R_1 = \tfrac{1}{2} \, \Omega$
### Step 1: Divide the resistances
$\frac{R_T}{R_1} = \frac{3}{4} \div \frac{1}{2} = \frac{3}{4} \times \frac{2}{1} = \frac{6}{4} = \frac{3}{2}$
### Step 2: Multiply by total current
$I_1 = 6 \times \frac{3}{2} = 9 \, A$
The resistor with lower resistance receives more current. Dividing fractions made it possible to calculate this directly.
## Try It Yourself
1. $\frac{5}{6} \div \frac{2}{3}$
2. You have a 60 V source divided evenly among resistors. Each gets $\tfrac{1}{4}$ of the total voltage. How many resistors are there?
3. A circuit section receives only $\tfrac{1}{2}$ of the available power. Another section receives $\tfrac{1}{3}$ of that. What fraction of the original power does the second section get?