Measuring Up #4

I was at a gathering recently, and a little girl (eight or nine years old) was telling my teacher friend Jellyfish about her Steiner primary school.

JELLY: So what kind of maths are you learning?
LITTLE GIRL: Measurement.
JELLY: That's what I'm doing with my kids at the moment! Are you doing millimetres and metres?
LITTLE GIRL: No.
JELLY: Oh. Centimetres?
LITTLE GIRL: (blank) ...
JELLY: (wary) Inches?
LITTLE GIRL: (shakes head) ...
JELLY: What are you measuring in?
The LITTLE GIRL holds up her arm.
LITTLE GIRL: Cubits!
JELLY: (in horror) Cubits.
LITTLE GIRL: Yep. It's the length of this part of your arm.
JELLY: Like in Noah's Ark.
LITTLE GIRL: Yes.
JELLY: (cries)
We didn't get a chance to ask the little girl exactly which type of cubits she was learning about. Roman cubits (444.5mm)? Greek cubits? (463.1mm)? Arabic cubits (650.2mm)? Mesopotamian cubits (533.4mm)? Babylonian cubits (496.1mm)? Not to mention Salamis cubits, Persian cubits, the Pergamon cubit the Mesoamerican cubit and the various different Jewish cubits.