If you don't know what he actually knows (hence the boredom and frustration) then just blast through the work. Rather than insist that all of the work be done, just ask him to pick about 3 (or less) of each type of problem and do them. If he can do them with no problem mark that lesson off as learned. Just because the work is there doesn't mean you have to make him do every single problem!
I had a big problem with this the first couple of days. This is our first year of "official" homeschooling through the local public school independent study program. Right now it looks like Wolf will be done with the majority of the 1st grade work by Christmastime and a good portion of it is simply review for him that I am just checking to make sure he has it down.
If he knows it why make him learn it? The problem now is just figuring out what he already knows!
