Enter the number of units needed per day to calculate how many pens are needed in written prescriptions for 30-day and 90-day supplies for various insulin pens (U-100, U-200, U-300, U-300 Toujeo Max, U-500) and insulin vials (U-100, U-500). Also provide an option to enter number of units per meal(s) to make the final calculation.

For example:
A 30-day supply of U-100 pens
= [(___ units/day)*30 days]/300 units per pen

Thank you.