Variables let you store and reuse the value of expressions.
Add a variable. Tap ABC at the top of the keyboard, select the variable you want to add, enter the mathematical expression, then tap Done.
Edit variables. Tap , tap Edit, then tap the variable you want to edit.
Quickly edit a variable. Type the variable name, type « = », then enter the new expression.
Delete a variable. Swipe the variable left, then tap Delete.
View variables. Swipe down the result or tap to show variables.