If half of five was two what would a third of ten be?
The answer is 1. This is because you halve the amount of letters in fi-ve to get two therefore a third of t-e-n is three divided by three giving you one.
Why this works
This riddle plays with the idea of using the number of letters in each word rather than their numerical values. When you take "five," it has four letters, and half of that in terms of letters would be two, as you only count "fi" and "ve." Similarly, "ten" has three letters, and a third of that would be one letter, which is "t." So, the clever twist here is focusing on the letters instead of the numbers!