The Junk Seller - Basic Profit and Loss

Cost Price (CP): This is the amount of money a junk seller or shopkeeper pays to buy items from others. Visually, imagine a shopkeeper handing over money to a large truck driver to get sacks of newspapers or plastic.

Selling Price (SP): This is the price at which the junk seller sells the collected items to a big shop or factory. In your mind, visualize the seller receiving cash from a buyer and putting it into their cash box.

Profit (Gain): If the Selling Price is more than the Cost Price ($SP > CP$), the seller makes a profit. Visually, this is like a bar graph where the 'Selling Price' bar is taller than the 'Cost Price' bar, and the difference is the extra money earned.

Loss: If the Selling Price is less than the Cost Price ($CP > SP$), the seller suffers a loss. Imagine starting with 10 coins to buy something but only getting 8 coins back when you sell it; the 2 missing coins represent the loss.

The Rate List: A table that shows the price of 1 kg of different items (like waste paper, brass, or iron). To find the total cost, you look at the 'Price per kg' on the list and multiply it by the weight of the item you have.

Loan and Interest: A loan is money borrowed from a bank or a person for a specific time. Interest is the extra money paid back along with the borrowed amount. Visualize a timeline where you borrow $₹ 100$ today and pay back $₹ 110$ after a month; the extra $₹ 10$ is the interest.

Multiplication by Expansion (Box Method): A way to multiply large numbers by breaking them into smaller parts (like $63 \times 10$ being $60 \times 10$ and $3 \times 10$). Visually, this looks like a grid where you calculate areas of smaller boxes to find the total sum.