In The sewers ( you and Leo are a couple in this and Casey and d/n are in this timeline and as a couple)

Leo (14) was doing math homework what his smart brother Donnie, assigned him that's when y/n comes in and see Leo struggling.

Y/n: What's the problem babe?

🟦Leo: Math Problems.

Y/n: I can help you with that let me see.

Leo gives y/n his homework and sees

Y/n: Oh here's an easy one what's 6 x 3

Leo shrugs cuz he don't know?

Y/n: 6 x 3!

🟦Leo: I dont know babe.

Y/n: 6 X 3!

🟦Leo: I don't

Y/n: 6 x 3!

🟦Leo: I legit don't know?

Y/n: 6 threes

🟦Leo: Idk babe what is it?

Y/n: WHAT IS IT?

.............. that's when y/n knew she don't know

Y/n: Get Casey

🟦 Leo: Why?

Y/n: CASEY JONES JR!

Casey in the future appears.

🏒 Casey Jones Jr: Whats the problem, lady y/n?

Y/n: Homework, hun.

Y/n gives Casey Jones Leo's homework.

🏒Casey Jones: Whats 6x 3

🟦Leo: I don't know!

🏒Casey: 6 X3

🟦Leo: I don't know!

🏒Casey: what's 6 + 6

🟦Leo: Oh! 12

🏒Casey: NOW ADD 6

🟦Leo: I DON'T CASEY WHAT IS IT!

🏒Casey: WHAT IS IT!

.........................The moment Casey knew he did know either.

🏒Casey: Get your math Teacher!

🟦Leo: Who?

🏒Casey: DONNIE!

Boom appears Donnie.

🟪 Donnie: BOOM, What?

🏒Casey: Homework!

Casey gives Donnie Leo's homework.

🟪Donnie: I TAUGHT YOU THIS LEO! WHATS 6 X 3!

🟦Leo: I DON'T KNOW!

🟪Donnie: LOOK, if Mikey have 6 times 3 amount of peaches, HOW MUCH PEACHES THEY WILL HAVE!

🟦Leo: HOW MUCH?

🟪Donnie: HOW MUCH!

..................... The Moment our smart Donnie knew he doesn't know the answer to the question but Donnie was looking at Mikey making peach cream out of peaches.

🟪Donnie:................... 1,2,3,4,5,6

The creator: is 18.

🐀Splinter: FINALLY SOMEONE ELSE HAS THE ANSWER