wool - n - gather

Decrease refers to decreasing number of stitches in a row/round. This can be achieved with any stitch you are working with. Make a stitch up to the point of making the last yarn over and pull though two loops, move on to the next stitch and do the same any number of times required, finish off all stitches with yarn over and pull through all remaining loops. This combines all of the stitches into one.