x1 (li) is represented in numeral base x2 (li or name) as x3 (me'o).
If x2 is a number using li, it should ideally be expressed in a base-neutral way. Instead of representing it with a particular base's notation, use te'a or pi'i to appropiately represent the factors or «su'i pa» to increase the base by one if needed. For example base twenty-four would be «li xa pi'i vo» instead of «li revo». See also ju'u, namcu, mekso.