I admit I find it rather amusing that Canadian sweepstakes law requires that entrants answer a math question. Which are usually so easy that anyone can do it. So what's the point?
Then again, these are FL's were talking about here. So there goes the logic...
It's not that sweepstakes law requires that entrants answer a math question exactly. It's that for-profit gambling - spending money in exchange for a random chance at profit - is illegal outside certain limited contexts (charity events, licensed casinos, and provincial lotteries), so sweepstakes incorporate skill-testing questions so they can legally claim to be games of skill rather than chance. Businesses came up with the skill-testing question as a loophole, and the courts have resigned themselves to allowing it, though they've made determinations as to minimum difficulty of the math question to qualify.
It's essentially the same reason why every "find this thing in something you buy and win a prize" contest in the US says in the fine print that you can also enter by mailing in a 3x5 card instead, and has to declare in any promotional material "purchase not necessary for entrance" or something along those lines. That way they can legally claim not to be for-profit gambling either; you can enter for free, so it's not gambling. (Which is also a work-around done in Canada sometimes for sweepstakes instead, but the skill-testing question's more popular there; probably because it's a lot less work for companies, I'd guess.)