Question 253639
<pre>
Then if x = its hundreds digit then
x+1 = its tens digit and x+2 is its units digit

So the number is 

100x + 10(x+1) + (x+2) =

100x + 10x + 10 + x + 2 =

111x + 12

If you let x=1, you get it immediately, because

111(1) + 12 = 111 + 12 = 123  

and  123 + 2 = 125 = 5^3 and 123 - 2 = 121 = 11^2 

Edwin</pre>