While tutoring my daughter for her summer math class, I was just having some math fun with an amortization table on a lazy Labor Day afternoon.

Some discoveries and direct applications:

1) If you were being offered by a condo salesman a condo payable in 5 years; and if the amount being financed or spread over 5 years is P 1 million, at the rate of 17.25% (in-house financing), at the end of the 5th year you would have paid a total of P 499,231.84 in interest charges alone.  That's easily rounded off to half of the amount you loaned!

2) When a bank says they will offer to double your money in 5 years, that means that they are providing you with an interest rate of 31.6% per annum.  That's too good to be true, and obviously, if someone poses that rate to you, there's a large chance that this could be a scam.  Then again, this is the index by which people are pushed to go into any form of entrepreneurial venture (vis a vis leaving money in a bank).  Provided that one's business generates a 31.6% profit steadily over the 5 year period, one would have more than doubled their money by then.

For those of you who want a copy of the Excel amortization table, please feel free to send me a PM indicating your email address.  I will email the amortization table to you as an attachment.