diff --git a/common/__init__.py b/common/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/common/conversion/__init__.py b/common/conversion/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/common/conversion/removeEmptyDecimals.py b/common/conversion/removeEmptyDecimals.py
new file mode 100644
index 0000000..80e62ec
--- /dev/null
+++ b/common/conversion/removeEmptyDecimals.py
@@ -0,0 +1,15 @@
+def removeEmptyDecimals(n):
+  """
+    Removes .0 from a float if it doesn't add any extra value to the number.
+
+    Parameters:
+      n (float): the value to parse
+
+    ```
+    >>> removeEmptyDecimals(2.0)
+    2
+    >>> removeEmptyDecimals(2.5)
+    2.5
+    ```
+  """
+  return int(n) if int(n) == n else n
\ No newline at end of file
diff --git a/common/inputChecking/__init__.py b/common/inputChecking/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/common/inputChecking/boolInput.py b/common/inputChecking/boolInput.py
new file mode 100644
index 0000000..eddfd61
--- /dev/null
+++ b/common/inputChecking/boolInput.py
@@ -0,0 +1,18 @@
+def boolInput(question, error='Skriv in J eller N\n', yesNoLetters=('j', 'n')):
+  """
+  Asks the user a yes/no question and returns a bool based on the input.
+
+  Parameters: \\
+    prompt (str): The prompt asking the user for input \\
+    error? (str): The message to be printed on parsing error \\
+    yesNoLetters? ((str,str)): The letters to be used for representing yes and no in low caps
+  """
+  yesLetters = [yesNoLetters[0], yesNoLetters[0].capitalize()]
+  noLetters = [yesNoLetters[1], yesNoLetters[1].capitalize()]
+  while True:
+    try:
+      choice = input(question)
+      assert choice in yesLetters + noLetters
+      return choice in yesLetters
+    except AssertionError:
+      print(error)
\ No newline at end of file
diff --git a/common/inputChecking/choiceInput.py b/common/inputChecking/choiceInput.py
new file mode 100644
index 0000000..8e78d1b
--- /dev/null
+++ b/common/inputChecking/choiceInput.py
@@ -0,0 +1,16 @@
+def safeQuestion(prompt, choices):
+  """
+  Prompts the user to make a choice and asserts that the choice is valid.
+
+  Parameters: \\
+    prompt (str): The prompt asking the user for input \\
+    choices ([str]): The choices that the user can choose (in low caps)
+  """
+  allChoices = choices + [choice.capitalize() for choice in choices]
+  while True:
+    try:
+      answer = input(prompt)
+      assert answer in allChoices
+      return answer.lower()
+    except AssertionError:
+      print('Skriv inn enten', ', '.join(choices[:-1]), 'eller', choices[-1])
\ No newline at end of file
diff --git a/common/inputChecking/typeCheck.py b/common/inputChecking/typeCheck.py
new file mode 100644
index 0000000..534e9dd
--- /dev/null
+++ b/common/inputChecking/typeCheck.py
@@ -0,0 +1,19 @@
+def inputTypeCheck(
+    prompt,
+    type,
+    error="Kunne ikke tolke input. Har du skrevet det inn riktig?"
+):
+  """
+  Typechecks an input, and only returns the input when it could be successfully parsed.
+
+  Parameters: \\
+    prompt (str): The prompt asking the user for input \\
+    type (fun): The function to be used for parsing \\
+    error? (str): The message to be printed on parsing error
+  """
+  while True:
+    inputValue = input(prompt)
+    try:
+      return type(inputValue)
+    except ValueError:
+      print(error)
\ No newline at end of file
diff --git a/common/test/__init__.py b/common/test/__init__.py
new file mode 100644
index 0000000..e69de29