Clay brought a $500 series EE bond and redeemed it after 4 years for $329.20. How much interest did Clay earn?

To calculate the interest earned on Clay's Series EE bond, we need to subtract the initial investment amount (the bond's face value) from the redemption amount.

The face value of the bond is $500, and the redemption amount after 4 years is $329.20. The difference between the two will give us the interest earned.

Interest Earned = Redemption Amount - Face Value
Interest Earned = $329.20 - $500
Interest Earned = -$170.80

Since the interest earned is negative (-$170.80), it means that Clay actually incurred a loss instead of earning interest.