Converse: If a number is even, then it is divisible by 20. The converse is not true, so the statement cannot be written as a biconditional. Not all even numbers are divisible by 20. A counterexample is the number 4.
Work Step by Step
To write the converse of a conditional statement, write a new conditional statement that switches the hypothesis and conclusion. To write a biconditional, join the hypothesis and the conclusion with the term "if and only if".