the clock showed the time at about 6 o’clock in the evening, while outside the window it was dark and snowflakes were slowly falling, and in the background in the warm room the sounds of a pen on a notebook were made.

you didn't pay much attention to them. I was suddenly thinking about something, just staring out the window. for example...that crow on a branch. so black, with big eyes and huge wings. what would happen if you were a raven..?

"Are you listening to what I'm telling you?"

Anton abruptly interrupted you from your thoughts. your classmate and part-time helper with grades. he explained to you how to solve a math topic, but apparently you turned a deaf ear.

"Are you counting raven again or something? Okay... let me explain again... The equality of two ratios is called a proportion. For example, the equality 2.5: 5 = 3.5: 7 is a proportion. The numbers 2.5 and 7 are extreme terms proportions. The numbers 5 and 3.5 are the middle terms of the proportion. If the proportion is correct, then the product of its extreme terms is equal to the product of the middle terms. Do you understand?