Ask HN: Job offer only lists shares that I'd receive, how much are they worth?

I just received a job offer for a senior engineering position at a fairly early (working on series B) startup. For the equity (stock) they only list the number of shares I will receive, the cliff, and vesting schedule.

How am I supposed to know the value of the shares? Should I ask them to disclose the total shares float, and what percentage of the total shares my equity is?