ONE:
What the class thought: generator of all numbers, not actually considered a number; characterized reason
What it actually is: Beginning, independence, innovation, leadership

There might be a link between these two interpretations and I'm sure someone with a keener sense of Arithmancy would be able to pick it up. From what I see you could loosely link the generator of all numbers to beginning so we weren't all that wrong in our assumption despite not being right.

TWO:
What the class thought: first female number; characterized opinion and division
What it actually is: Harmony, unity, relationships, collaboration, duality, humans/human magic

This is actually really funny because it couldn't have been more wrong meaning some of our readings were wrong. See, the class thought division and such but it's really unity and collaboration and all that good stuff. Whoops.

THREE:
What the class thought: first male number, combination via addition of 1 (unity) and 2 (division); characterized harmony
What it actually is: Imagination, positivism, playfulness, creative expression, house elves/house elf magic, complex thought

Lol this one's actually just as funny. They went off on some harmony tangent when all it really was is imagination and positivism. Merlin knows what those two have in common, I didn't help come up with that interpretation, I was lost half the time. Funny how wrong it was though.

FOUR:
What the class thought: second female number, represented space and matter; characterized by justice and order
What it actually is: Building, formation, hard work, endurance, sober-mindedness, practicality, organization

The only thing I really see fitting might be justice and order mixing with practicality but that's only if you really try to see it. Otherwise this one was another dud in the guessing train. You think the class would have been better at this.

FIVE:
What the class thought: union of first male and female numbers; characterized by love and marriage
What it actually is: Change, transition, progressive thinking, resourceful, freedom, versatility, physical world, physical touch

There is nothing progressive or resourceful about love, lemme just say this and marriage is pretty far out as well. See this is what happens when you start thinking all mushy like while deducing what numbers are. Wherever that Pythag guy is, I bet he's disappointed.

SIX:
What the class thought: female; characterized by creation, originality, or beginnings
What it actually is: Balance, nurturing, service-oriented, responsibility/duty, family focus, domestic and work issues, stability

Starting to think I should just label these all as far of. I can't even begin to see a link between these two. Like what even?

SEVEN:
What the class thought: male; characterized by conflict or individuality
What it actually is: Analysis, research, solitude, wisdom, spiritual focus, investigative, mysticism, magic

Ah hah! Somethng. Individuality and solitude kinda have some play by each other, you know, so in that sense it makes it a little correct despite the obvious fact that once again for the most part the class was wrong and the book was right. This is common place stuff though so expected. Bless the textbook, we'd be lost without it.

EIGHT:
What the class thought: female; characterized by compromise, cooperation, or balance
What it actually is: Authority, finances, business, success, material wealth, self-mastery, complex thought/reasoning, fluidity, movement

....I dunno...I just....there's nothing. The class was dead wrong here.

NINE:
What the class thought: male; characterized by peace, stability, or enlightenment
What it actually is: Endings, tolerance, metamorphasis, cosmic, teaching, global awareness, perfection, power/strength, short-lived, immediacy

This comparison here tells me we shouldn't persue careers in Arithmancy...for our own good and the good of the wider wizarding world.