diff --git a/QUSTOJ/1737.c b/QUSTOJ/1737.c
new file mode 100644
index 0000000..f600f80
--- /dev/null
+++ b/QUSTOJ/1737.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+//Written by Kiritow. 求最大公约数
+long gcd(long a,long b)
+{
+    if(a==0||b==0)
+    {
+        if(a+b==0)
+        {
+            return 0;
+        }
+        return (a==0)?b:a;
+    }
+ 
+    while(a!=b)
+    {
+        if(a>b)
+        {
+            a=a-b;
+        }
+        else
+        {
+            b=b-a;
+        }
+    }
+    return a;
+}
+int main()
+{
+    int a,b,c,d;
+    char op;
+    scanf("%d/%d%c%d/%d",&a,&b,&op,&c,&d);
+    int x,y;
+    switch(op)
+    {
+    case '+':
+        x=a*d+b*c;
+        y=b*d;
+        break;
+    case '-':
+        x=a*d-b*c;
+        y=b*d;
+        break;
+    case '*':
+        x=a*c;
+        y=b*d;
+        break;
+    case '/':
+        x=a*d;
+        y=b*c;
+        break;
+    }
+    int ret;
+    while((ret=gcd(x,y))!=1)
+    {
+        x/=ret;
+        y/=ret;
+    }
+    //*/
+    int mx=x>y?x:y;
+    printf("%d/%d%c%d/%d=%d/%d\n",a,b,op,c,d,x,y);
+    return 0;
+}