Can you knit a double knit wool cardigan with 3ply wool?

It depends what size, but you'll need about 100 grams (3.2 ounces) of wool.

It depends on the size and style of jumper you want, the stitch pattern being used, and the weight of yarn you have. A large sweater with a dense stitch pattern (such as lots of cables) will require...

depends on the wool, the needles and the size of the jumper. Try to get hold of the knitters handy book of sweater patterns by ann budd, that has lots of charts to help work this out

Make a loop, pull it through, repeat. I learned with a rhyme. In through the front door, once around the back, peek through the window and on jumps Jack. a little young, but hey, it worked. Its hard...

Cotton is softer. Additionally, cotton is a cellulose fiber taken from the seed pod of a plant. Wool is a keratin fiber and is a variety of fur that sheep have.