Hey there!
The first one:
The 20 means it has 20 protons. The 42 means the sum of protons and neutrons is 42, so that means 20 protons plus 22 neutrons is 42 total. There is no charge noted, so the number of electrons is equal to the number of protons.
This atom has 20 protons, 22 neutrons, and 20 electrons.
The second one:
The 20 means it has 20 protons. The 44 means the sum of protons and neutrons is 44, so that means 20 protons plus 24 neutrons is 44 total. There is no charge noted, so the number of electrons is equal to the number of protons.
This atom has 20 protons, 24 neutrons, and 20 electrons.
Hope this helps!