What’s 50% of $120.00?

While shopping yesterday, I witnessed a mother telling her pre-teen (~11 years old) son to ask the sales associate for an item’s sale price. Here’s what blows my mind: Mom’s coat was located on a rack with a big sign announcing “50% off ALL red-lined items”. Even though the coat’s tag had a big red line through the original $120.00, Mom sent the son to obtain the sale price.

1. Shouldn’t Mom have been able to calculate the sale price herself?
2. The majority of 5th graders know how to count by tens and how to divide into halves.
3. Finally, the sales associate ought to be slapped for using a calculator.