If both premises are particular premises, then either one can be done first. For universal statements use shading to denote areas that are empty. If the conclusion is a universal statement, this will be relatively straightforward. If it is on the line, it doesn't count. All mammals are animals.
All mammals are animals.
All tigers are mammals. All unicorns are mammals. Some tigers are animals. Some unicorns are animals. Use Venn diagrams to determine whether the following standardized categorical syllogisms are valid or invalid.