Math for Knitters - Casting On a Multiple of X + Y

Cast-on a multiple of 14 + 3? Or 12 + 8? Or any combination of numbers? What does that mean? Whether these instructions are for a cast-on number in knitting or a foundation chain number in crochet, I explain it here. Information on things you'll see in this video: The pattern for the sweater I'm wearing (not my design, knit in a discontinued cotton yarn), can be found here: http://knitty.com/ISSUEspring03/PATTsitcomchic.html The needles in the thumbnail photo are Knitter's Pride Nova Cubics straight needles: http://astore.amazon.com/verypinkcom-20/detail/B00FGE4Z6A The pink yarn in the thumbnail photo is Knit Picks Wool of the Andes Bulky in color Crush. The bamboo DPN I use as a pointer in the video is Knitter's Pride Bamboo: http://astore.amazon.com/verypinkcom-20/detail/B00FGF1V20 The nail polish I'm wearing is Julep, color "Maddy": http://www.julep.com/rewardsref/index/refer/id/683913/