What is the mass of the copper metal in the case below?

This is a simple observational task. You must look carefully at the pointed end of the rider to ascertain exactly at which mark it is pointing. In this case, you will see that the rider points to the slightly longer dash halfway between the five and the six.

Therefore the answer is 5.5. You are saved from counting along mark by mark by having these halfway marks made longer. When you see one of these indicated, you will know that it is a .5 answer.