<p>Helping students grasp the &quot;why&quot; of algebra through patient explanations， Hirsch and Goodman gradually build students' confidence without sacrificing rigor. To help students move beyond the &quot;how&quot; of algebra (computational proficiency) to the &quot;why&quot; (conceptual understanding)， the authors introduce topics at an elementary level and return to them at increasing levels of complexity. Their gradual introduction of concepts， rules， and definitions through a wealth of illustrative examples - both numerical and algebraic-helps students compare and contrast related ideas and understand the sometimes subtle distinctions among a variety of situations. This author team carefully prepares students to succeed in higher level mathematics.</p>