You have to use 2nd order thinking. I give you $10. You lend $9 to Joe. Joe takes that money and deposits it in your bank. So, now you have $19 in your bank. Y

You have to use 2nd order thinking. I give you $10. You lend $9 to Joe. Joe takes that money and deposits it in your bank. So, now you have $19 in your bank. You lend Sally $8.1 of the $9 that Joe gave you. Sally deposits the $8.1 in your bank. Your bank now has $27 in deposits. Continue until you've basically got 10x what you originally had in deposits.