Short and simple answer: yes
Here's how:
1. Create a Notes page
2. Go to Menu>Insert>Math Box (or do Ctrl+M).
3. Type the name of your variable in the mathbox and press enter.
4. If you want to change the settings, position your cursor inside the math box and go to Menu>Math Box Options> Math Box Attributes (or Ctrl+Menu>Math Box Attributes) and change settings to your needs.
I hope this was helpful.