Can't see fraction clearly on page 95 of MTOC

[DengLinPiano]

"17 from 12 is...working scale, mark out 1/4" to 18, as shown''

What is the missing fraction in the above sentence meant to be?

[TTailor]

Can you post a photo of the instruction you are having trouble with? I dont have my copy handy.

[TTailor]

Found it online. If it is the correct page, the fraction is 1/12 working scale.
It forms the side back seam and back armhole points in a jacket draft.
Yes?

[DengLinPiano]

Found it online. If it is the correct page, the fraction is 1/12 working scale.
It forms the side back seam and back armhole points in a jacket draft.
Yes?

The page is this


Could you also tell me what the fraction in the sentence, "Make a..."step" at this point for the seam", is? The sentence is below the sentence which I was first referring to.

[TTailor]

Mark a 1/4" for the seam, means to draw a squared off area that indicates there is 1/4" seam allowance on that seam. The same squared off end of the seam is on the corresponding seam on the front.

It should be shown in the diagram that goes with the instructions.