diff --git a/src/dataANDcalc/java/stack/CalculatorByStack.java b/src/dataANDcalc/java/stack/CalculatorByStack.java
index 9b85a8e..5f0f932 100644
--- a/src/dataANDcalc/java/stack/CalculatorByStack.java
+++ b/src/dataANDcalc/java/stack/CalculatorByStack.java
@@ -19,11 +19,12 @@ public class CalculatorByStack {
 
     public void calculate(String expression) {
         int length = expression.length();
+        String numStr = "";
         for (int i = 0; i<length;i++){
             String str = expression.substring(i,i+1);
             String operRegex = "[+\\-*/]";
             Pattern operPattern = Pattern.compile(operRegex);
-            if (operPattern.matcher(String.valueOf(str)).matches()) {
+            if (operPattern.matcher(str).matches()) {
                 if("+".equals(str)){
                     if(operStack.isEmpty()){
                         operStack.push(ADD);
@@ -57,8 +58,15 @@ public class CalculatorByStack {
                     operStack.push(DIV);
                 }
             }else {
-                int num = Integer.parseInt(str);
-                numStack.push(num);
+                numStr += str;
+                if (i == expression.length()-1){
+                    numStack.push(Integer.parseInt(numStr));
+                    continue;
+                }
+                if (operPattern.matcher(expression.substring(i+1,i+2)).matches()){
+                    numStack.push(Integer.parseInt(numStr));
+                    numStr = "";
+                }
             }
         }