She picked up one of the Snowy Owls that was "calling to her" then took it up to the register.
"Is that it?" The cashier said with looking up at her.
"Yes, I did. How much do I owe you!"
"Hmmm, an Owl and two brother kittens. Hmmm... well, kittens usually go for about 10 to 20 Gallons based on breed, and Owls usually go for: hmmm... about 30"
"Hmmm, what's the price for two Tabby kittens"
"Tabby? Oh, that'll be approximately 6 Gallons in total"
"So, 3 for each cat?"
"Yes, that's right!"
"Okay, let's see" she reached into the back pocket of her casual clothes and pilled out some big, shiny, and really round silver coins. "So that's, 30 gallons plus 6 gallons—- hmmm, 30 plus 6 equals... 36; is that right?"
"Yes, yes, it is— wow! You sure are smart" the cashier said with a smile.
"Gee, thanks. Hogwarts is great for learning magic, not so good for learning basic every day still such as Math or as the British call it: Maths".
"You're welcome" the cashier replied, "Anyway— here you go..." she handed the pets back to Sophia.
"Thanks" she replied quickly before turning to head out the door.