OT: Simple maths question

I heard this on a gameshow: "Answer quickly, what's half of 99?" - Allegedly most people say 44.5. Why? I said 49.5. I halve 100 then take another half off. Or you could halve 90 then add half of 9. Either way, how can people make this mistake?

Reply to
Jimmy Wilkinson Knife
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Because they can't do sums (it's not maths, it's arithmetic).

Reply to
Tim Streater

Many people are dumb. I took half a hundred and took off another half.

Reply to
Ed Pawlowski

Exactly what I did. I was surprised when John Richardson (the OCD and clever comedian) got it wrong, but then maybe that was staged.

Reply to
Jimmy Wilkinson Knife

How do these people get by? I wonder if they all get short changed? On= ly the other week Aldi tried to give me =A310 less change than I should = have got - although he did seem a bit confused, he was new there.

I'm not pedantic, I call them all maths.

-- =

Yorkshire man takes his cat to the vet. Yorkshireman: "Ayup, lad, I need to talk to thee about me cat." Vet: "Is it a tom?" Yorkshireman: "Nay, I've browt it wi' us."

Reply to
Jimmy Wilkinson Knife

They don't need to do mental arithmetic often enough to matter.

Unlikely when most flash their card and so there is no change.

More fool you for not using your card or phone.

Reply to
Rod Speed

Another reason to use the self service checkout if paying cash. Or pay by card.

Very interesting that these 'genuine' mistakes at the checkout are almost always in favour of the store.

Reply to
Dave Plowman (News)

Half of 66 is 33; half of 88 is 44; half of 99 is...

Reply to
Max Demian

For those who don't understand the difference between odd and even numbers that they should have been taught in year one of arithmetic.

Reply to
Dave Plowman (News)

Four-and-half-ty, four and a half

Reply to
Chris Green

They probably aren't but how many when given £10 too much are going to make a fuss about it?

Reply to
dennis

I just check my change, but I use self service anyway as it's faster, bu= t not all supermarkets have those. My Asda does, but Morrisons only hav= e them for people with mini baskets, and Aldi and Lidl don't have them a= t all.

Or more likely the checkout worker. It seems to be a standard thing, no= t noticing you've given them a =A320. Some people actually say 20 out l= oud when they hand one over.

-- =

Police arrested two kids yesterday, one was drinking battery acid, and t= he other was eating fireworks. They charged one and let the other one of= f.

Reply to
Jimmy Wilkinson Knife

Exactly, which when added together make 49 and a half. I still can't think of how to make ther glaring error above.

Reply to
Jimmy Wilkinson Knife

I actually add up like that sometimes. I'll come to an answer of twelvety three. It's interesting that some people immediately know what number that is and some don't.

Reply to
Jimmy Wilkinson Knife

That (halve 100 then take another half off) is what I would do. 44.5 doesn't make sense.

Reply to
Mark Lloyd

4.54.5 :-)

3*10+3 = 33

4*10+4 = 44 4.5*10+4.5 = 49.5

Where's the 44.5? (its not at Burger King :-))

Actually, I would start by "promoting" 99 to 100, divide by 2 (easy here), and correct for the "promotion". Essentially 99 / 2 = (100 / 2) - (1 / 2). It's the "distributive property", but much less complicated.

BTW, "mathematics" is NOT plural. Consider that you don't go into a store and say "one mathematic, please".

Reply to
Sam E

Which is equal to 49.5, as in 4.5 * 10^1 + 4.5 * 10^0 = 45 + 4.5 = 49.5

BTW, to get that REALLY correct, replace 10 with r and specify that r =

  1. r^1 = r and r^0 = 1.
Reply to
Mark Lloyd

123?

Essentially I applied the "distributive property of multiplication over addition" rule (but it was much easier, since I wasn't explaining it too). I separated 99 into 100 and -1, numbers easy to divide by 2, and then put them back together.

BTW, "where's the 44.5?" reminded me of the 1980's Burger King commercials where someone was saying "Where's the beef?".

Reply to
Mark Lloyd

Yes. Eighty, ninety, tenty, eleventy, twelvety.

Yes, same here.

Dunno, I always fast forward ads.

Reply to
Jimmy Wilkinson Knife

It was originally a plural. This, and the Math vs Maths debate is covered in the Radio 4 More or Less programme:

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Reply to
Max Demian

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