Section $4\mathrm{.}7$ discusses non$-$annual cash flows. The previous finance math formulas had mostly discussed annual cash flows. Do the same formulas work for non$-$annual cash flows?

Yes and no$.$ The formulas only work for non$-$annual lump sums.

Yes. Match the cash flow frequency to the interest rate frequency $($monthly to monthly, quarterly to quarterly$)$

No$.$ The formulas only work for annual cash flows.

Yes. Match the interest rate frequency to the frequency of cash flows $($monthly to monthly, quarterly to quarterly$)$