How to: The Backwards Loop Cast On
This is perhaps the easiest cast on to learn and master. It creates a very loose and thin edging to the knitted fabric and is a good all-purpose cast on. It is also known as the backward loop cast on, the e-wrap cast on, or single cast on.
Start with a slip knot on your needle. Hold your needle in your right hand and use your fingers to keep the yarn tail out of the way. Grasp the working yarn in your left hand.
Pass the working yarn around your thumb from back to front.
Slip the needle tip under the loop around your thumb.
Pull your thumb out of the loop and tug on the working yarn to tighten up the stitch.