Is there a way to reference a constant value in a data table without making a column for it?

[#1]

I have a simple table with a column for mass of powder measured and another column for the resulting volume calculation. I could include an additional column for the known density, but I was wondering if there is a way to have a reference to a constant instead creating a column for it where all the values are identical. 

[#2 · Accepted solution]

Make a table variable. Click the red triangle in the Table Panel of the data table and choose New Table Variable. 

[#3]

Thanks Dan! This is perfect. I appreciate the tip.

[#4]

I hope I am understanding what you want.  So lets say, you have a column A and a column B and you want to add them together and multiply by a constant value of 7.  The formula for the new column would be

( :A + :B ) * 7;

Is this what you are asking for?