How much skeins yarn do I need?

I want to make a 68" x 90" blanket. I will be using Lion Brand Wool-Ease Thick and Quick yarn in size 13 needles.

Gauge for 4" by 4" using size 13 (9mm) needles is 9sts x 12 rows.
They come in 6 oz skeins, 170 gms, 108 yards, 98 meters.

Also, I have to cast on 153 stitches right? Just checking if I did the math right :smiley: Thanks:woot:

When you knit with that yarn and needles do you get 9 sts over 4"? It’s not clear if that’s what’s on the label gauge or if that’s what you get.