Life is a Test: A Series of Pony Logic Puzzles

by Brony_of_Brody


Hogwarts Doesn't Offer Maths

"Maths?" Silverstream repeated. The young hippogriff stared at the professor of the day, Rarity, in confusion.

"Oh goodness, yes," Rarity nodded. "Twilight felt that the School of Friendship should at least include basic education in the curriculum. Celestia knows where I'd be without it."

Gallius let out a groan and threw his clawed font legs in the air. "Urgh, maths is so boring though!"

Sandbar gave the griffon a stern look. "Doesn't change the fact we all need to learn how to count properly."

"Thank you, Sandbar," Rarity smiled at the young colt. She then turned to the blackboard behind her, picked up a white piece of chalk from the pot to the right, and wrote out a series of numbers: 1 to 10, in ascending order.

Gallius stared incredulously at the board, then at Rarity. "Uh, we already know how to count to ten. We're not THAT bad."

Rarity, with her back still facing the class as she continued to write, gave a huge grin. "Oh not that, dear, I assure you." She then went on to chalk down '= 100' next to the sequence of numbers. A collective "Huh?" rang throughout the classroom.

The white unicorn turned back to the class. "I've written down, as you can see, an incorrect sum. What I want is for the class to write down a correct answer to it, using the standard operators."

"Yona not know operators," Yona said, raising her hoof.

"She means symbols such as an addition sign, the subtraction sign, and so on," Cozy Glow explained.

"Precisely. Now observe." Rarity then started to fill in the blank spaces between the numbers, until finally she had written '1 + 2 + 3 + 4 + 5 + 6 + 7 + (8x9) = 100. "This is one such way I could correct the sum. As you can see, I've used nine operators: seven plusses, one multiply sign, and one pair of brackets."

"But there are others," Cozy deduced, seeming to have cottoned on to Rarity's proposed challenge. "There's a certain one you want us to find, right?"

"Oh, my, such a smart filly!" Rarity smiled at Cozy. "Yes, using the standard operators I mentioned, along with the minus symbol and the division symbol, I want the class to find the lowest number of operators needed to make this a correct sum."

"Can we move any of the numbers?" Ocellus asked.

"Not at all. You may, however, combine numbers together to form a larger number. So for example you can treat 3 and 4 as 34."

"Really? All this as part of a maths lesson?" Smolder the dragon asked.

"Well, it's to gauge your current level mostly, so Twilight can better the curriculum," Rarity explained. She looked over the class, none of whom seemed eager to give it a try...except for Ocellus, who was scribbling down possible combinations as soon as Smolder started talking. "Twilight also mentioned a prize for all those who get the correct answer."

Upon hearing those words, Smolder gasped and started scribbling away on her piece of paper. Soon, the rest of the class joined in, with Gallius complaining about how this was designed to punish stupid students, but he picked up his quill and started scrawling away...