about 13
3*3*2*1 = 18
there are 899 whole numbers that have three digits.
24
There are 5*4*3 = 60 such numbers.
about 13
With repeated digits, 43 = 64 Without repeated digits, 4*3*2 = 24
6: 146, 164, 416, 461, 614, and 641.
3*3*2*1 = 18
there are 899 whole numbers that have three digits.
525
There are 5*4*3 = 60 such numbers.
Numbers above 99 and under 1000 are 3-digits, all 900 of them.
24
There are 5*4*3 = 60 such numbers.
Using only arrangements of the given digits: without repeating digits, 15. with repetition, 39. The answer does not include numbers such as 2^3 = 8 or 3^(2+1) = 27
900