diff --git a/2018/Serg-Lapata/hw-1/task.rb b/2018/Serg-Lapata/hw-1/task.rb
new file mode 100644
index 000000000..c9298b947
--- /dev/null
+++ b/2018/Serg-Lapata/hw-1/task.rb
@@ -0,0 +1,50 @@
+def triangle(height, start_value)
+  rows = []
+
+  height.times do |row_number|
+    current_value = start_value
+    row = [current_value]
+    k = 1
+    row_number.times do
+      current_value = current_value * (row_number - k + 1) / k
+      row << current_value
+      k += 1
+    end
+    rows << row
+  end
+
+  print_triangle(rows)
+end
+
+def check_integer(int)
+  int.positive? ? int : raise('Got invalid number')
+end
+
+def start_value
+  int = ENV['BASE_NUMBER']
+
+  unless int
+    puts 'Enter start value'
+    int = gets
+  end
+
+  check_integer(int.to_i)
+end
+
+def print_triangle(rows)
+  width_element = rows.last.max.to_s.length + 1
+  width_last_row = width_element * rows.last.length
+
+  rows.each.with_index do |row, row_number|
+    row_data = row.map do |element|
+      element.to_s.center(width_element)
+    end.join.center(width_last_row)
+
+    puts "#{row_number}: #{row_data}"
+  end
+end
+
+puts 'Enter height triangle'
+height_triangle = gets.to_i
+check_integer(height_triangle)
+triangle(height_triangle, start_value)