Fingers Crossed

It seems hard to believe that only two skeins of yarn will make my Featherweight.  I have it on Sharon's authority that they do and the yarn is Americo Cotton Flamme with 100 grams and 400 metres to a skein   -

 

but  still, I'm  nervous.

So I ask you, how's your math?  Here I am at 12 inches in an 18 inch sweater. 

 

Another  six inches of sweater, a three inch ribbed collar/button bands, and two sleeves to go. 

 

There are 34 grams of skein number one, remaining.  Too complicated for me.  It's slowing me own a bit, but  I'm knitting on with fingers crossed.