diff --git a/src/main/java/com/bytelegend/Challenge.java b/src/main/java/com/bytelegend/Challenge.java
index 20239d5..7eb218c 100644
--- a/src/main/java/com/bytelegend/Challenge.java
+++ b/src/main/java/com/bytelegend/Challenge.java
@@ -17,7 +17,7 @@ public static void main(String[] args) {
      * (`+`).
      */
     public static int multiplyBy31(int n) {
-        return 0;
+        return (n << 5) - n;
     }
 
     /**
@@ -32,6 +32,10 @@ public static int multiplyBy31(int n) {
      * addition sign (`+`).
      */
     public static int divideBy2ThenMinus1(int n) {
-        return 0;
+        if (n < 0) {
+            int m = -n;
+            return -(m >> 1) - 1;
+        }
+        return (n >> 1) - 1;
     }
 }