The smallest prime number is 2. So the numbers can be __2. Now for the tens digit, it can be 3,4,and 5 giving 3 possibilities. And finally, the hundreds digit can be 8 or 9.

So there are 6 numbers that satisfy these conditions.

Btw, if you want to double check, the numbers are 832, 842, 852, 932, 942, and 952.