diff --git a/18-microarch.Rmd b/18-microarch.Rmd
index 8299fd6..c7950eb 100644
--- a/18-microarch.Rmd
+++ b/18-microarch.Rmd
@@ -446,9 +446,9 @@ knitr::include_graphics('./images/chapter8/32bit_RCA.png')
 
 （1）并行进位逻辑
 
-假设两个N位数A和B相加，A记作a~N-1~a~N-2~$\ldots$a~i~a~i-1~\ldots a~1~a~0~，B记作b~N-1~b~N-2~$\ldots$b~i~b~i-1~$\ldots$b~1~b~0~。定义第i位的进位输入为c~i~，进位输出为c~i+1~，且将加法器的输入C~in~记作c~0~以方便后面描述的统一。每一位进位输出c~i+1~的计算为：$$c_{i+1}=a_{i}\ \&\ b_{i}\ |\ a_{i}\ \&\ c_{i}\ |\ b_{i}\ \&\ c_{i}=a_{i}\ \&\ b_{i}\ |\ (a_{i}\ |\ b_{i}）\ \&\ c_{i}$$
+假设两个N位数A和B相加，A记作a~N-1~a~N-2~$\ldots$a~i~a~i-1~\ldots a~1~a~0~，B记作b~N-1~b~N-2~$\ldots$b~i~b~i-1~$\ldots$b~1~b~0~。定义第i位的进位输入为c~i~，进位输出为c~i+1~，且将加法器的输入C~in~记作c~0~以方便后面描述的统一。每一位进位输出c~i+1~的计算为：$$c_{i+1}=a_{i}\ \&\ b_{i}\ |\ a_{i}\ \&\ c_{i}\ |\ b_{i}\ \&\ c_{i}=a_{i}\ \&\ b_{i}\ |\ (a_{i}\ |\ b_{i})\ \&\ c_{i}$$
 
-设$g_{i} = a_{i} \ \&\ b_{i}，p_{i} = a_{i} \ |\ b_{i}$，则c~i+1~的计算可以表达为：
+设$g_{i} = a_{i} \ \&\ b_{i},\  p_{i} = a_{i} \ |\ b_{i}$，则c~i+1~的计算可以表达为：
 
 $$c_{i+1}=g_{i} \ |\ p_{i} \ \& \ c_{i}$$