diff --git a/05_sumAll/sumAll.js b/05_sumAll/sumAll.js
index 00880c7..8f94ce5 100644
--- a/05_sumAll/sumAll.js
+++ b/05_sumAll/sumAll.js
@@ -1,6 +1,31 @@
-const sumAll = function() {
+const sumAll = function(start, end){
+  if(end<0 || start<0 || typeof(start) !== "number" || typeof(end) !== "number"){
+    return "ERROR"
+  }else{
+    if(end < start){
+      end1 = end
+      end2 = start
+    }else{
+      end1 = start
+      end2 = end
+    }
+    return (end1 + end2)*(end2/2)}
+  };
+
+
+//   let total = 0;
+//   for (let i = start; i <= end; i++) {
+//    total = total + i;
+  
+//    }
+//    return total;
+// };
+ 
+
+
+
+
 
-};
 
 // Do not edit below this line
 module.exports = sumAll;
diff --git a/05_sumAll/sumAll.spec.js b/05_sumAll/sumAll.spec.js
index 1a9fb7c..a171e5f 100644
--- a/05_sumAll/sumAll.spec.js
+++ b/05_sumAll/sumAll.spec.js
@@ -4,19 +4,19 @@ describe('sumAll', () => {
   test('sums numbers within the range', () => {
     expect(sumAll(1, 4)).toEqual(10);
   });
-  test.skip('works with large numbers', () => {
+  test('works with large numbers', () => {
     expect(sumAll(1, 4000)).toEqual(8002000);
   });
-  test.skip('works with larger number first', () => {
+  test('works with larger number first', () => {
     expect(sumAll(123, 1)).toEqual(7626);
   });
-  test.skip('returns ERROR with negative numbers', () => {
+  test('returns ERROR with negative numbers', () => {
     expect(sumAll(-10, 4)).toEqual('ERROR');
   });
-  test.skip('returns ERROR with non-number parameters', () => {
+  test('returns ERROR with non-number parameters', () => {
     expect(sumAll(10, "90")).toEqual('ERROR');
   });
-  test.skip('returns ERROR with non-number parameters', () => {
+  test('returns ERROR with non-number parameters', () => {
     expect(sumAll(10, [90, 1])).toEqual('ERROR');
   });
 });