Added to maths and strings (#1642)

* Added to maths and strings

* added changes suggest by cclauss

strings/upper.py

@@ -0,0 +1,26 @@
+def upper(word: str) -> str:
+    """ 
+    Will convert the entire string to uppercase letters 
+    
+    >>> upper("wow")
+    'WOW'
+    >>> upper("Hello")
+    'HELLO'
+    >>> upper("WHAT")
+    'WHAT'
+    
+    >>> upper("wh[]32")
+    'WH[]32'
+    """
+
+    # converting to ascii value int value and checking to see if char is a lower letter
+    # if it is a capital letter it is getting shift by 32 which makes it a capital case letter
+    return "".join(
+        chr(ord(char) - 32) if 97 <= ord(char) <= 122 else char for char in word
+    )
+
+
+if __name__ == "__main__":
+    from doctest import testmod
+
+    testmod()