How to use math formula recognition

Choose the math icon from the toolbar illustration
1.
Choose the math icon from the toolbar
Write your formula with "= ?" at the end illustration
2.
Write your formula with "= ?" at the end
Press the arrow and your formula will appear illustration
3.
Press the arrow and your formula will appear
Switch to pen tool and strike through your formula for the answer to show illustration
4.
Switch to pen tool and strike through your formula for the answer to show