diff --git a/概念/乘法.md b/概念/乘法.md
index 42edfc1..9918217 100644
--- a/概念/乘法.md
+++ b/概念/乘法.md
@@ -19,17 +19,17 @@ $$ \sum_{k=1}^{n}{m} = \underbrace{m + m + m + \cdots + m}_{n} = m \times n $$
 
 ## 乘法口诀表
 
-| X   | 1   | 2   | 3   | 4   | 5   | 6   | 7   | 8   | 9   |
-| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
-| 1   | 1   | 2   | 3   | 4   | 5   | 6   | 7   | 8   | 9   |
-| 2   | 2   | 4   | 6   | 8   | 10  | 12  | 14  | 16  | 18  |
-| 3   | 3   | 6   | 9   | 12  | 15  | 18  | 21  | 24  | 27  |
-| 4   | 4   | 8   | 12  | 16  | 20  | 24  | 28  | 32  | 36  |
-| 5   | 5   | 10  | 15  | 20  | 25  | 30  | 35  | 40  | 45  |
-| 6   | 6   | 12  | 18  | 24  | 30  | 36  | 42  | 48  | 54  |
-| 7   | 7   | 14  | 21  | 28  | 35  | 42  | 49  | 56  | 63  |
-| 8   | 8   | 16  | 24  | 32  | 40  | 48  | 56  | 64  | 72  |
-| 9   | 9   | 18  | 27  | 36  | 45  | 54  | 63  | 72  | 81  |
+| $\times$ | 1   | 2   | 3   | 4   | 5   | 6   | 7   | 8   | 9   |
+| -------- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
+| 1        | 1   | 2   | 3   | 4   | 5   | 6   | 7   | 8   | 9   |
+| 2        | 2   | 4   | 6   | 8   | 10  | 12  | 14  | 16  | 18  |
+| 3        | 3   | 6   | 9   | 12  | 15  | 18  | 21  | 24  | 27  |
+| 4        | 4   | 8   | 12  | 16  | 20  | 24  | 28  | 32  | 36  |
+| 5        | 5   | 10  | 15  | 20  | 25  | 30  | 35  | 40  | 45  |
+| 6        | 6   | 12  | 18  | 24  | 30  | 36  | 42  | 48  | 54  |
+| 7        | 7   | 14  | 21  | 28  | 35  | 42  | 49  | 56  | 63  |
+| 8        | 8   | 16  | 24  | 32  | 40  | 48  | 56  | 64  | 72  |
+| 9        | 9   | 18  | 27  | 36  | 45  | 54  | 63  | 72  | 81  |
 
 ## 竖式计算