diff --git a/lib/sumArray.ts b/lib/sumArray.ts
new file mode 100644
index 0000000..a0b4b18
--- /dev/null
+++ b/lib/sumArray.ts
@@ -0,0 +1,13 @@
+export function sumArray(array: number[] | null): number {
+  if (Array.isArray(array) && array.length > 0) {
+    array.sort((a, b) => a - b);
+    array.shift();
+    array.pop();
+    return array.reduce((acc, currentValue) => acc + currentValue, 0)
+  }
+  return 0;
+}
+
+console.log(sumArray([6, 2, 1, 8, 10]), 16);
+console.log(sumArray([6, 0, 1, 10, 10]), 17)
+console.log('slice(1, -1): [ 6, 0, 1, 10, 10 ]', [6, 0, 1, 10, 10].slice(1, -1))