Hi. What's a Knifty Knitter?
I can tell you that if I make a long scarf, I would usually make it about as long as the person it is for is tall, unless I run out of yarn or have just a little left and go ahead and use it up. Patterns should give measurements and how much yarn to purchase. I think knitting is fun. Seeing those stitches on the needle, watching the ball of yarn turn into something I've made still amazes me.
I should never overestimate my basic arithmetic skills.