"10M bonds" denotes $10,000 in principal amount to be received by the bondholder at maturity. Each bond pays 6% annual interest of $60; thus, 10 bonds pay a total of $600 per year into semi annual payments of $300. at maturity, the bondholder will receive the $10,000 face amount plus the final semi annual payment. ($10,000 + $300 = $10,300).