diff --git a/d05-IP-Addressing.md b/d05-IP-Addressing.md
index 0ba241e..fc0f7ea 100644
--- a/d05-IP-Addressing.md
+++ b/d05-IP-Addressing.md
@@ -525,14 +525,14 @@ C类地址 = 255.255.255.0
 
 | - | - |
 | -- | -- |
-| `172.16.50.0` | <b>10101100.00010000.0</b>0110010.00000000 |
-| `172.16.60.0` | <b>10101100.00010000.0</b>0111100.00000000 |
-| `172.16.70.0` | <b>10101100.00010000.0</b>1000110.00000000 |
-| `172.16.80.0` | <b>10101100.00010000.0</b>1010000.00000000 |
-| `172.16.90.0` | <b>10101100.00010000.0</b>1011010.00000000 |
-| `172.16.100.0` | <b>10101100.00010000.0</b>1100100.00000000 |
-| `172.16.110.0` | <b>10101100.00010000.0</b>1101110.00000000 |
-| `172.16.120.0` | <b>10101100.00010000.0</b>1111000.00000000 |
+| `172.16.50.0` | **10101100.00010000.0**0110010.00000000 |
+| `172.16.60.0` | **10101100.00010000.0**0111100.00000000 |
+| `172.16.70.0` | **10101100.00010000.0**1000110.00000000 |
+| `172.16.80.0` | **10101100.00010000.0**1010000.00000000 |
+| `172.16.90.0` | **10101100.00010000.0**1011010.00000000 |
+| `172.16.100.0` | **10101100.00010000.0**1100100.00000000 |
+| `172.16.110.0` | **10101100.00010000.0**1101110.00000000 |
+| `172.16.120.0` | **10101100.00010000.0**1111000.00000000 |
 
 通告的汇总地址会是什么呢？