How do you find the atomic mass/mass number of an atom? a. add the number of protons and electrons together b. subtract the number of protons by the number of neutrons c. subtract the number of protons by the number of neutrons d. add the number of protons and neutrons together

The answer is C subtract the number of protons by the number of neutrons and by the way both b and c are the same. ;)

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .