What is the highest product that you can make using the 5 digits on the right only once. You can place the numbers in any order and in any square.
HARD MODE - Do not use a calculator.
LEGENDARY MODE - If I use unique 1-digit whole numbers, where should I put the largest, 2nd largest, 3rd largest, 4th largest, and 5th largest? How do you know?
Credit to @fawnpnguyen for the idea.