At a library, the tickets are arranged for a party in each tube. Model: ⬟⬟⬟⬟⬟⬟⬟ ÷ ⬟⬟⬟⬟⬟⬟⬟ ÷ ⬟⬟⬟⬟⬟⬟⬟ (each '/' starts a new row) Prompt: Choose the equation written as columns x items in each column.