A free original bilingual lesson on number series under declared rules. Use constant differences, constant ratios, regularly changing gaps, alternating subsequences, a stated previous-two-term rule and specified square or cube families. Keep term position separate from term value, check an internal missing term from both sides and test every supplied entry. Six worked cases, an analogy, a quick reference and six practice questions with full solutions and option explanations support exact reasoning. The questions use stated rule families or allowed-rule menus; finite data do not establish uniqueness among every imaginable formula. These selected families do not claim exhaustive RRB series or complete reasoning coverage.