In many el-hi math books, when using the value in problem solving, the instructions will state to let π = 3.14, since that is a decent approximation for the younger students’ purposes.
¥ I use the Alt-key combinations, myself. To get my yen, hold down Alt, then on the number pad, hit 157, then release. ¥ There are several combinations. ¢ is Alt+155, etc.
I am enjoying this arc so far…I do not recall ever reading it. :)