Yes, you're getting it!:yay:
And right, if you ever make the bigger size, using the same yarn and needles, go up to 120.
Just a bit of clarity on the 20 sts-- the rib pattern uses 5 sts, so the number of stitches has to be a multiple of 5. For the decreases, you divide the sts into 4 quarters, so the number of sts has to be divisible by 4. The lowest number that will accomodate both the 5 and 4 is 20, so the number of sts in the pattern has to be divisible by 20.
The hat is stretchy, which is different from measuring say, a sweater. If the pattern is stockinette stitch, the fabric will lie flat and it's easy to work out. But with something that's all rib and supposed to stretch out when it's on, then you have to rely on the designer. The hat, when measured round, may or may not be actually 22" or 25", but those are the numbers to work with if you want to make adjustments. Meaning, if you do the math with a different yarn and gauge and come up with 22" or 25", it will work. The 22" and 25" numbers I got from taking the gauge of the yarn she listed-- which was 5.5 sts per inch-- and dividing it by the number of sts she had you cast on-- 120 and 140. That came to 21.82 (rounded to 22) and 25.45 (rounded to 25). So then you just take whatever gauge you're getting per inch and multiply that by 22 or 25. Then, because of the need to have a multiple of 20 to make both the pattern and the decreases work, you have to go to the nearest 20 and you're set.
If you think you'll be making this pattern again, you might want to write this down to figure it out easily next time:
1. MY GAUGE IS _________ PER INCH.
2. I WANT TO MAKE THE [SMALLER OR BIGGER] SIZE.
3. THE GAUGE [ANSWER #1] X 22 [FOR THE SMALL] OR 25 [FOR THE BIGGER] = _______________.
4. THE NEAREST NUMBER TO [ANSWER #3] THAT IS DIVISIBLE BY 20 IS ____________. THIS IS THE NUMBER OF STS TO CAST ON.
4. WHEN I DIVIDE INTO QUARTERS FOR THE DECREASES, MY NUMBERS WILL BE X - 2, X, X AND X.
Keep us posted as it comes along. . .