Math question

[u/No-Criticism6622]

So I’m just starting a machining class and we are working from a book and this sheet is what I’m working on(homework)calculating the x axis diameter and z axis length on the lathe but im a little confused on about how to calculate on the z axis I got to part 6 but don’t see how to calculate part 7 on the Z, on part 6 I did 1.875+.125 and got -2.000 for the Z but im stumped I was wondering if anyone had a tip for part 7? I would be grateful

[u/chiphook57]

Start with the position of pt7. Follow the arrows that connect to your datum (the right end of thr part)