diff --git a/问题/均贫富.md b/问题/均贫富.md
index 62deba3..e0a45c9 100644
--- a/问题/均贫富.md
+++ b/问题/均贫富.md
@@ -14,7 +14,7 @@ $ a - x = b + x \quad (a \in \Bbb{N}, b \in \Bbb{N}, a>b) $
 $
 \begin{aligned}
 2x &= a - b  &(移项并交换等式两侧) \\\\
- x &= \frac{a-b}{2}  &(等式两侧同除以2)
+ x &= \dfrac{a-b}{2}  &(等式两侧同除以2)
 \end{aligned}
 $