What is the mass of an ink pen on a triple-beam balance

The mass of an ink pen is constant no matter what instrument you use. If you weigh the ink pen on a simple platform balance, it would weigh approximately 16 grams. To measure this mass using a triple beam balance, follow these instructions:

1. Empty the pan, then move the three sliders on each of the beams to left ton the zero mark.
2. Place the ink pen on the pan. As a result, the beams are no longer on the zero mark. Slide the beams until the pointer is at zero. 
3. To read the weight, add all the numbers in the three slider beams.