50g

Hello Jose, is very interesting the idea of a creating lessons or 
tutorials for the machine, even thou the HP website have some 
tutorials, there is always something extra to show, For example in the 
HP forums for the calculators, somebody posted the following system:
p=(0.02^2-r^2+d^2-2*(0.02)*d*cos(80))/(2*(0.02-r-d*cos(80))
sin(26.67)=(d*sin(80))/(p-r)
0.008=d+r-0.02

Showing the proses to solve this system in the calculator is a good 
lesson.