I have to confess I wasn't clear on what he was trying to convey without digging in a bit deeper. This blog post from a teacher in response to his post clarified things: <a href="https://denisegaskins.com/2008/07/01/if-it-aint-repeated-addition/" rel="nofollow">https://denisegaskins.com/2008/07/01/if-it-aint-repeated-add...</a>