Reductio and negation
Assuming a formula, deriving a contradiction and discharging the assumption as a negation, with double negation for the last step and modus tollens for when no assumption is needed.
About 20 minutes7 activities Paper packet
Assuming a formula, deriving a contradiction and discharging the assumption as a negation, with double negation for the last step and modus tollens for when no assumption is needed.
About 20 minutes7 activities Paper packet