Math & English Interactive Teaching Board

Key Teaching Examples:
Three-Digit Grouping: -
Written English: -
Comma ( , ) separating major 3-digit periods
Hyphen ( - ) between 21 and 99
Connector "and" (Replaces comma ONLY when terminal hundreds is 0)
Scale Name (Thousand/Million/Billion)

Grammar Breakdown: The Punctuation & Connector Rules

    Side-by-Side Sync Tools:
    Demonstration Presets:
    ◀ LEFT DISPLAY [Track A]
    Step 1: Locate Target → Arch to Decider
    Step 2: Transformation Result
    RIGHT DISPLAY [Track B] ▶
    Step 1: Locate Target → Arch to Decider
    Step 2: Transformation Result

    Rounding Mathematical Rules (教學核心口訣)

    • 1. Underline the Target Digit: Locate the specified place value and underline (_) that digit.
    • 2. Draw the Wall (Dashed Line): Draw a vertical dashed line immediately to the right of the target digit to partition the number into LEFT SIDE and RIGHT SIDE.
    • 3. Arch Over to the Decider Digit: Look ONLY at the immediate first digit on the right:
      • If 5, 6, 7, 8, 9 (≥ 5) → ROUND UP (+1): Add +1 to the target digit on the left (carry over if needed).
      • If 0, 1, 2, 3, 4 (< 5) → REMAIN UNCHANGED: The target digit and left side remain completely unchanged.
    • 4. Clear the Right Side to Zeros: Regardless of whether it was Round Up or Remain Unchanged, all digits on the right side become 0!