Betwixt and Between: Sub-Teens & Slacks: Simplicity 4540
Separates were an idea that had been around for a while, at least to the days of the shirtwaist around 1900, and were made even more popular by Claire McCardell in the 1950s. McCardell liked to have separates made in the same fabric to look like dresses as you see in the print and the plaid skirts and blouses here in the top row. McCardell like a covered-up top and a bare top which went with the same skirt, while many others realized harmonizing coordinates simply made it easier to get dressed.
This patterns dates to the early 1960s and shows us how a moment in time and in the life cycle could get dressed. Slacks on women were for informal occasions, like resort wear or dirty work, although women began wearing fancy silk slacks around the house for informal entertaining during the 1950s. On girls--and these patterns were for 8-14 sub-teen sizes--slacks were for play time or at-home time. By the late 1960s, pants on women were for every occasion, despite the protests of conservative dresses. But here you can see there was still a level of formality, or perhaps we should say of a level of harmony expected, as these coordinates were made of the same fabrics as the skirts or the vest. The days of a pair of jeans with any kind of top were still in the future.
The skirt is a simple rectangle with pleats at the waistline and both the skirt and the pants close with a zipper. The vest is lined to the edge, and buttons closed. Notice the collared blouse has cuffs as well. Cottons are recommended, but so are linens, silks, and even lightweight woolens for cooler months. These garments took a fair amount of sewing effort and ability. Maybe possessed by the sub-teen herself, but more likely by her mother or some older relative.
Notice this isn't really all that different from the capsule wardrobe that got invented in the 1940s and keeps getting rediscovered as something new about every 15 years or so. There is something persistently appealing about an easy, but polished way to get dressed.