Your students think they know division — until they hit 0 ÷ 0. This discovery-based mini lesson uses cognitive conflict to help students reason through why 0 ÷ 0 is indeterminate, not just memorize a rule. Includes a rich extension connecting to algebra and the foundational idea of limits. THE LESSONThis 20–45 minute inquiry-based lesson creates genuine mathematical discovery by pitting two familiar rules against each other: "Any number divided by itself is 1" → so 0 ÷ 0 = 1? "Zero divided by an