All or Nothing

All or Nothing is a study of how fourth-grade high-achievers solve — or don't solve — math problems like this one:

Find the number
It is smaller than 100.
If you divide it by 7, there is no remainder.
If you divide it by 3, the remainder is 2.
If you divide it by 5, the remainder is 1.

Interestingly, many of them refuse to write down any intermediate work, and many of them won't persevere long enough to check that a number does in fact meet all three criteria.