remove class based exercises

sumAll/sumAll.js

@@ -1,5 +1,20 @@
-var sumAll = function() {
-
+var sumAll = function(a, b) {
+  if (a > b) {
+    let temp = a
+    a = b
+    b = temp
+  }
+  if (
+    a < 0 || b < 0 ||
+    typeof a != 'number' || typeof b != 'number'
+  ) {
+    return 'ERROR'
+  }
+  let sum = 0
+  for(let i = a; i < b + 1; i++) {
+    sum += i
+  }
+  return sum
 }
 
 module.exports = sumAll