To convert the mixed number \( 5 \frac{3}{7} \) into an improper fraction, follow these steps:
- Multiply the whole number by the denominator: \( 5 \times 7 = 35 \).
- Add the numerator to this product: \( 35 + 3 = 38 \).
- Place the result over the original denominator:
\[ \frac{38}{7} \]
So, \( 5 \frac{3}{7} \) as an improper fraction is \( \frac{38}{7} \).