I was presented with a power point slide by a friend about math education and one of his slides talked about "the seven benchmark numbers". He said that:

The seven benchmark numbers to develop a "complete" number sense are: $0, \frac{1}{10}, \frac{1}{2}, 1, 10, 12,$ and $100$. These numbers form the foundation of the mathematics curriculum in primary and secondary education.

Unfortunately, when pressed to do so, my friend was unable to explain why these numbers were "benchmarks." Does anyone know what he may be referring to or, better yet, does anyone know where he gets this information from?