Kakashi had thought he was used to kids whining about his cruel teaching methods, but really he had underestimated his own brats, if what he was getting now was the normal level of complaining. Or maybe it was the fact that to get all the houses together he'd had to place his first class on a Saturday. Bah.
"You each have a number. Find the people who have the same number; they will be your teammates."
The bushy-haired one figured it first, though not by much. "But this means every team will have one member of each house!"
"Brilliant," he drawled back, "but this doesn't get you toward your partners faster. Get moving, brats."
There was some offended whispering at the term he had used, and at being forced to mix with other houses, but Kakashi didn't listen. He'd heard people call him a lot of worse things, and at the end of the day they were going to be using them all.
"For the first task you'll be going in turns. Team one, to me." He pulled his book out of his left pocket with one hand, and showed the kids the contents of his right hand. "Anything goes, any spell or dirty trick you can think of. If it's stupid but it works, it isn't stupid. If you maim me, points for you. I won't complain. Grab one of these from me, and you pass the class. If you can't, you'll be coming here tomorrow and the next weekend as well, until you do."
The same girl voiced people's concern once again. "... But... there's only three bells! And we're four!"
He smiled widely under his mask. "Yes. Exactly. Begin."
He was going to teach them Inter-house cooperation if it killed them.