In Oz during my school days decades ago, most males in 8th grade (which then was seen as an extra 'finishing' for Primary School, rather than the beginning of Technical School - Damn those Yank ideas!!!) every male did 'technical stuff' while females did 'home ec stuff'.

As I remember from then, 1-3/4 x 3-3/4 was 'dressed 2x4'...'dressed sizes' always meant that the rough cout standard sizes were planed smooth, taking a planne 1/8 off each face.