Final answer:
In problem-solving, identifying the unknown quantities is the next step after defining the problem and gathering information.
Step-by-step explanation:
In problem-solving, after defining the problem and gathering information, the next step is to identify exactly what needs to be determined in the problem, known as the unknown quantities. To do this, it is helpful to make a written list of the unknowns. This is important especially in complex problems where it might not be obvious what needs to be found or in what sequence.