At a shoe store, all shoes are on sale for $20 off the regular price. If p represents the regular price, write an expression to represent the sale price.

p - 2o = sale price

To represent the sale price of the shoes, we need to subtract the discount of $20 from the regular price.

The expression to represent the sale price would be: p - 20.

In this expression, 'p' represents the regular price, and subtracting 20 from 'p' gives us the discounted or sale price.