The stem is combined from words Science, Technology, Engineering, and Mathematics. All of them have connected with each other. This year is different we have included the physical subject. In the stem class, I have learned about the Atomic mass and Atomic number and more. Atomic mass is the number of proton and neutron plus together. One tip that we could find atomic mass is taking mass number can be divided by 2, which mean proton and neutron are half of each other. Atomic number is the number of the protons are in the atom.