Dividers are wonderful and very ancient tools. The simplicity of their form and function belie the fascinating world of geometry that they unlock.
Span a particular dimension and you can lock it off to be transferred as many times as you like. Divide a circle accurately into 6 segments by walking its radius around the circumference, find centres, subdivide distances and all without having to use the mathematical side of your brain.
Because the same steel points that take the measurement also create the mark or scribe line, there is minimal opportunity for errors to creep in. You can use them to form perpendiculars, scribe arcs and circles, position fastenings or simply to explore appealingly related proportions.
No numbers, just measurement in its purest, simplest and most beautiful form.