Question 1090200
By contained once I assume you mean used once so the numbers would look like
2xyz, x2yz, xy2z, xyz2 where x,y,z are unique digits not equal to 2.
So then for each case,
{{{N=7*6*5=210}}}
There are 4 cases as shown so the total number of digits would be,
{{{N[tot]=4*210}}}
{{{N[tot]=840}}}