The only metric to imperial conversion I remember is kilometers to miles since it’s pretty close to the golden ratio.
Even if you don’t remember that the golden ratio is 1.6 and a bit, you can approximate it by using successive terms of the Fibonacci sequence.
1, 1, 2, 3, 5, 8, 13 …
So 8 miles is about 13km (actually 12.87)
The letters that make up words is a common blind spot for AIs, since they are trained on strings of tokens (roughly words) they don’t have a good concept of which letters are inside those words or what order they are in.