We've just squeezed into Xmas day here in Australia but I'll get one more support in before Santa rocks up.
You will need to insert some JavaScript code into your numeric question. Click on the "Advanced" button at the bottom of the question then click on the "Custom JavaScript Verification" tab (top right hand corner).
My JavaScript isn't very strong but this should work.
Assuming your question is Q1, enter the following ...
var count=0
if(document.mainform["Q1"])
{
if((document.mainform["Q1"].value>=11)&&(document.mainform["Q1"].value<=20))
{
count=count+1;
}
}
if (count>0)
{
strErrorMessage="You must enter a response in the range of 1-10 & 21-50. Please review your answer before continuing.";
}
else
{
strErrorMessage="";
}
Note - you should enter the numeric question range as minimum value=1 and maximum value=50.