diff --git a/ch2/lineards/bit_manipulation.cpp b/ch2/lineards/bit_manipulation.cpp
index 3d30874..98eafbd 100644
--- a/ch2/lineards/bit_manipulation.cpp
+++ b/ch2/lineards/bit_manipulation.cpp
@@ -3,10 +3,10 @@
 #include <bits/stdc++.h>
 using namespace std;
 
-#define isOn(S, j) (S & (1<<j))
-#define setBit(S, j) (S |= (1<<j))
-#define clearBit(S, j) (S &= ~(1<<j))
-#define toggleBit(S, j) (S ^= (1<<j))
+#define isOn(S, j) (S & (1<<(j)))
+#define setBit(S, j) (S |= (1<<(j)))
+#define clearBit(S, j) (S &= ~(1<<(j)))
+#define toggleBit(S, j) (S ^= (1<<(j)))
 #define lowBit(S) (S & (-S))
 #define setAll(S, n) (S = (1<<n)-1)