Much like other CM books, I love that there are no time restraints around it. You keep working the same lesson until it is mastered and then you move on. I also love the focus on word problems and real world math. My kids like it for the history aspect – “Can you believe that candy was only a penny a piece!?”
I can’t say for some of the books later in the series (we are in Primary Math right now), but I do next to no prep work for math. I take a chunk of time as needed to write down problems in their math notebook on whatever we are studying. (I like to use http://www.themathworksheetsite.com and copy the problems into their notebook.) My younger daughter uses manipulatives (she’s 5) but my son (8) no longer uses manipulatives. We usually review the lesson outloud, have them do a few problems in their notebook and call it a day. Sometimes we’ll play a computer game or something to reinforce the math in a more fun way.
Time is not included it Primary – not sure about higher up….but I simply waited until my son showed an interest in learning how to tell time, then we would spend 5 minutes a day learning to tell time on a clock. I printed up worksheets from http://www.themathworksheetsite.com, and started with the o’clocks and worked our way forward to telling time to the minute. After a few months, he had it down. Measurement is covered in the end of primary math – after addition, subtraction, multiplication and division are mastered. But again, when my son showed an interest in ;earning measurements, we grabbed a tape measure and we measured everything! Money is also covered later in the book, but we also cover it as they are interested so they have a background in money before it is covered formally. And that reminds me – I love this BECAUSE I can do a lot of tweeking as it suits our needs, or leave it as is when it suits our needs!