Fractional backstitch is worked in exactly the same way as fractional cross stitch.

To make a ¼ stitch:

The ¼ stitches will look like this on your chart:

Depending at what angle the ¼ stitch is to be, bring the needle up at point 1, 2, 3 or 4 and then push it down into the centre of the square.

 To make a ¾ stitch:

A ¾ stitch is made by stitching the short arm first (like a ¼ stitch) It is then completed with a half stitch to make the other two arms.

The ¾ stitches will look like this on your chart:

Bring the needle up at point 1, down at point 2, up at point 3 and down at point 4.