diff --git a/du4/program.c b/du4/program.c
index 44cd1a9..426efd9 100644
--- a/du4/program.c
+++ b/du4/program.c
@@ -77,16 +77,28 @@ int main() {
         LABEL:
         switch(operation){
             case 1:
-                printf("%s\n", (roundf(strtof(number1, &ptr) + strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) + strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                if(strtof(number1, &ptr) != roundf(strtof(number2, &ptr)))
+                    printf("%s\n", (roundf(strtof(number1, &ptr) + strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) + strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                else
+                    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", (roundf(strtof(number1, &ptr) - strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) - strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                if(strtof(number1, &ptr) != roundf(strtof(number2, &ptr)))
+                    printf("%s\n", (roundf(strtof(number1, &ptr) - strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) - strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                else
+                    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", (roundf(strtof(number1, &ptr) * strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) * strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                if(strtof(number1, &ptr) != roundf(strtof(number2, &ptr)))
+                    printf("%s\n", (roundf(strtof(number1, &ptr) * strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) * strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                else
+                    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", (roundf(strtof(number1, &ptr) / strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) / strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                if(strtof(number1, &ptr) != roundf(strtof(number2, &ptr)))
+                    printf("%s\n", (roundf(strtof(number1, &ptr) / strtof(number2, &ptr)*100)/100 > strtof(result, &ptr) - 0.001 && roundf(strtof(number1, &ptr) / strtof(number2, &ptr)*100)/100 < strtof(result, &ptr) + 0.001) ? "OK" : "ZLE");
+                else
+                    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\n");