This is my first post...I'm a newbie!!! My question: when learning a new pattern (knitting or crocheting) directions will sometimes say,"multiple of 7 +3 sts" to establish the pattern...I understand what that means, but when it's NOT given and you want to increase or decrease the size (for example, of a baby blanket) how do you establish the pattern repeat??? Is there a formula for this??? Much appreciate your help