Thanks to everyone for the information! I don't think our school/the teacher will be high stress like all of this. I'm just wondering what we might expect.
My son has a documented processing disorder and has extended time written into his IEP, but he has never used it. He got a 87th percentile on CTY's math part this year, so he can answer questions on a timed test, but he has trouble on these timed fact tests.
On the little book I bought, he did 36/50 (I think) in two minutes on addition and 24/50 in two minutes on multiplication. He definitely knows his math facts but he has trouble processing it all fast enough. I guess we will just keep chipping away at it.