diff --git a/scala_project_2025/part1/src/main/scala/Main.scala b/scala_project_2025/part1/src/main/scala/Main.scala
new file mode 100644
index 0000000..c00b3ca
--- /dev/null
+++ b/scala_project_2025/part1/src/main/scala/Main.scala
@@ -0,0 +1,31 @@
+import scala.annotation.tailrec
+
+@main def main(): Unit =
+  // task 1 a)
+  val values = new collection.mutable.ArrayBuffer[Int] // immutable pointer
+  for (i <- 1 to 50)
+    values.append(i)
+
+  println(values)
+  println(iterative_sum(values.toArray))
+  println(recursive_sum(values.toArray))
+  println((0 to 10).map(fibonacci))
+
+// task 1 b)
+def iterative_sum(numbers: Array[Int]): Int =
+  var result = 0
+  for (num <- numbers)
+    result += num
+  return result
+
+// task 1 c)
+def recursive_sum(numbers: Array[Int]): Int =
+  @tailrec def inner(numbers: Array[Int], accumulator: Int): Int =
+    if numbers.length <= 0 then accumulator
+    else inner(numbers.tail, numbers.head + accumulator)
+  inner(numbers, 0)
+
+// task 1 d)
+def fibonacci(n: Int): BigInt =
+  if n <= 1 then BigInt(1)
+  else fibonacci(n - 1) + fibonacci(n - 2)