The smallest possible case is 11×11 = 121
Let the the maximal digit be x and the minimal digit be y
x ≧ y
The product is
(10x + y)(10y + x) < 1000
100xy+10x²+10y²+xy < 1000
10x²+101xy+10y² < 1000
Let y, the minimal digit, be small as possible, i.e., y=1
10x²+101x+10 < 1000
10x²+100x-990 < 0
The solution to that quadratic inequality is
-16.14 < x < 6.13
But since x is an integer, x = 1,2,3,4,5, or 6
61×16 = 976, and that is a 3-digit number
So
61×16, 51×15, 41×14, 31×13, 21×12, and 11×11
account for 6 cases.
Let y, be the next smallest digit possible i.e., y=2
10x²+101xy+10y² < 1000
10x²+101x(2)+10(2)² < 1000
10x²+202x-40 < 1000
10x²+202x-1040 < 0
The solution to that quadratic inequality is
-24.45 < x < 4.25
Since x is an integer, x = 1,2,3, or 4
But 42×24 = 1008, is too large
However,
32×23 = 736 and 22×22 = 484 account for 2 more cases.
That's 8 cases.
The minimal digit y cannot be 3 since 33×33=1089,
which is not a 3 digit number.
So there are only 8 such 3-digit products.
Answer: fewer than 9. In fact there are only these 8
61×16 = 976
51×15 = 765
41×14 = 574
31×13 = 403
21×12 = 252
11×11 = 121
22×22 = 484
23×32 = 736
Edwin