Here's one plan for knitting a disk: Start with 8 stitches in the first round. Assuming equal stitch heights, the circumference of the second round is roughly twice that of the first round so make one stitch into two stitches, i.e. increase every stitch.
One strategy for knitting a disk involves starting with 8 stitches in the initial round. Assuming uniform stitch heights, the circumference of the subsequent round is roughly twice that of the initial round; therefore, merge each stitch into two stitches, effectively doubling the number of stitches.