diff --git a/du4/program.c b/du4/program.c
index 9b035ee..5055940 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -65,16 +65,16 @@ int main(){
         LABEL:
         switch(operation){
             case 1:
-                printf("%s\n", (strtof(number1, &ptr) + strtof(number2, &ptr) == strtof(result, &ptr)) ? "OK" : "ZLE");
+                printf("%s\n", (strtof(number1, &ptr) + strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) + strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             case 2:
-                printf("%s\n", (strtof(number1, &ptr) - strtof(number2, &ptr) == strtof(result, &ptr)) ? "OK" : "ZLE");
+                printf("%s\n", (strtof(number1, &ptr) + strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) - strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             case 3:
-                printf("%s\n", (strtof(number1, &ptr) * strtof(number2, &ptr) == strtof(result, &ptr)) ? "OK" : "ZLE");
+                printf("%s\n", (strtof(number1, &ptr) + strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) * strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             case 4:
-                printf("%s\n", (strtof(number1, &ptr) / strtof(number2, &ptr) == strtof(result, &ptr)) ? "OK" : "ZLE");
+                printf("%s\n", (strtof(number1, &ptr) + strtof(number2, &ptr) > strtof(result, &ptr) - 0.001 && strtof(number1, &ptr) / strtof(number2, &ptr) < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
                 break;
             default:
                 printf("CHYBA");