Casting on doesn't get easier than this. Just make a series of twisted loops. The advantage is that it is very easy to teach to children. The disadvantage is that it tends to create too much extra yarn between stitches and the gauge is usually unlike the rest of the piece. The stitches usually end up very tight and difficult to knit into, also.

You can use it in a pinch (and I often recommend it as an easy way to cast on one stitch over a thumb gusset or glove finger), but a better basic go-to cast on is probably the Knit Cast On or the Long Tail Cast On.

You may also want to check out my tutorial for How to Make a Slip Knot.

This cast on could be used in the following patterns:

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