Knitting stitches together, as in k2tog, k3tog, etc. is a common right leaning decrease. “k2tog” is possibly the most commonly called for decrease in knitting, and is the mirror decrease of the “ssk.”
Knit 2 stitches together
Abbreviation: k2tog
As if to knit, put right needle into the second, then first stitch on left needle, then knit together as one stitch.
Knit 3 stitches together
Abbreviation: k3tog
As if to knit, put right needle into the third, then second, then first stitch on left needle, then knit together as one stitch.
Knit 4 stitches together
Abbreviation: k4tog
As if to knit, put right needle into the fourth, third, second, then first stitch on left needle, then knit together as one stitch.
Knit 5 stitches together
Abbreviation: k5tog
As if to knit, put right needle into the fifth, fourth, third, second, then first stitch on left needle, then knit together as one stitch.
See also: Purling Stitches Together, Knitting Stitches Together Through the Back Loops, Purling Stitches Together Through the Back Loops