diff --git a/labs05/task00.py b/labs05/task00.py
index ea96b5e..dd146ce 100644
--- a/labs05/task00.py
+++ b/labs05/task00.py
@@ -2,10 +2,11 @@
 # -*- coding: utf-8 -*-
 
 def suma(liczby):
-    pass
+    assert len(liczby) > 0
+    return reduce(lambda a, b: a+b, liczby)
 
 def main():
-    print(summa([1, 2, 3, 4]))
+    print(suma([1, 2, 3, 4]))
 
 if __name__ == "__main__":
     main()
diff --git a/labs05/task01.py b/labs05/task01.py
index e69de29..0a79a36 100644
--- a/labs05/task01.py
+++ b/labs05/task01.py
@@ -0,0 +1,7 @@
+import task00, sys
+
+def main():
+    print('%f' % (task00.suma(map(lambda x: float(x), sys.argv[1:]))))
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/labs05/task02.py b/labs05/task02.py
index e69de29..c16e445 100644
--- a/labs05/task02.py
+++ b/labs05/task02.py
@@ -0,0 +1,12 @@
+import task00, sys
+
+def main():
+    def a_to_f(a):
+        try:
+            return float(a)
+        except:
+            return 0
+    print('%f' % (task00.suma(map(a_to_f, sys.argv[1:]))))
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/labs05/task03.py b/labs05/task03.py
index e69de29..9c9af4a 100644
--- a/labs05/task03.py
+++ b/labs05/task03.py
@@ -0,0 +1,15 @@
+import task00, argparse
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument("numbers", nargs="+")
+    args = parser.parse_args()
+    def a_to_f(a):
+        try:
+            return float(a)
+        except:
+            return 0
+    print('%f' % (task00.suma(map(a_to_f, args.numbers))))
+
+if __name__ == '__main__':
+    main()
\ No newline at end of file
diff --git a/labs05/task04.py b/labs05/task04.py
index 4dfc78c..4dc1af5 100644
--- a/labs05/task04.py
+++ b/labs05/task04.py
@@ -6,7 +6,7 @@ Implementacja narzedzia ``wc`` z linuksa (word counter).
 Zwraca liczbę słów, znaków i linii.
 """
 
-import sys
+import sys, argparse
 
 
 def count_lines(text):
@@ -19,7 +19,7 @@ def count_words(text):
                 for line in text.split('\n')])
 
 def count_chars(text):
-    """ return number of words. """
+    """ return number of characters. """
     return len(text)
 
 def wc(text):
@@ -32,7 +32,22 @@ def wc(text):
 
 def main():
     """ main """
-    print(wc(sys.stdin.read()))
+    parser = argparse.ArgumentParser()
+    parser.add_argument('-l', help="number of lines", action="store_true")
+    parser.add_argument('-w', help="number of words", action="store_true")
+    parser.add_argument('-c', help="number of characters", action="store_true")
+    parser.add_argument('fn', nargs='?', type=file, default=sys.stdin, help='optional filename to read from')
+    args = parser.parse_args()
+    lines, words, chars = wc(args.fn.read())
+    if( args.l or args.w or args.c ):
+        if(args.l):
+            print(lines)
+        if(args.w):
+            print(words)
+        if(args.c):
+            print(chars)
+    else:
+        print(lines, words, chars)
 
 
 if __name__ == "__main__":