27+48

tailwindhome
tailwindhome Posts: 19,439
edited July 2019 in The cake stop
There's an interesting 'thing' going round on twitter

27 plus 48 is 75

But what's your thought process to get to the answer

Post your answer below (before you read everyone else's)

It's interesting how people process this differently
“New York has the haircuts, London has the trousers, but Belfast has the reason!
«1

Comments

  • tailwindhome
    tailwindhome Posts: 19,439
    For me it's
    40+20 = 60
    7+8 = 15
    60+15 = 75
    “New York has the haircuts, London has the trousers, but Belfast has the reason!
  • daniel_b
    daniel_b Posts: 12,003
    48 + 20 = 68
    68 + 7 = 75
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  • shirley_basso
    shirley_basso Posts: 6,195
    40+20 = 60
    7+8 = 15
    60+15 = 75
  • Pross
    Pross Posts: 43,479
    For me it's
    40+20 = 60
    7+8 = 15
    60+15 = 75

    This originally but it may have been because I saw your answer before thinking about it. I went back to it and did 27 + 50 then took off 2.
  • lesfirth
    lesfirth Posts: 1,382
    Daniel B wrote:
    48 + 20 = 68
    68 + 7 = 75

    Simple
  • pblakeney
    pblakeney Posts: 27,382
    For me it's
    40+20 = 60
    7+8 = 15
    60+15 = 75
    Me too. Probably something to do with the way we were taught.
    I find the way these things are done by children these days strange. Different methods, but the same results.
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
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  • awavey
    awavey Posts: 2,368
    48 + 2 = 50
    27-2 =25

    25+50 = 75...

    or am I missing something obvious here
  • tailwindhome
    tailwindhome Posts: 19,439
    awavey wrote:
    or am I missing something obvious here

    There's no trick and nothing you're missing.
    It's just interesting that people have different thought processes to get the same answer.
    “New York has the haircuts, London has the trousers, but Belfast has the reason!
  • briantrumpet
    briantrumpet Posts: 20,518
    Which buttons to press on the calculator.

    Well, no. Did anyone else learn to use those 'calculating machines' where you turned a handle round numbers of times for multiplication? In a maths lesson, before we were allowed to have the fun of using them, we had to do mental calculation to get ballpark figures, because of the risk of jiggling the thing along too far and getting out by factors of something.

    Anyway, O-levels done without calculators, but with log tables and slide rules (modern school children don't know what these are).

    And the answer to the question... not quite sure, TBH - I think a sort of mixture, dumping the smaller number on top of the bigger one. Calculating VAT at 17.5% in one's head was always fun.
  • rjsterry
    rjsterry Posts: 29,690
    edited June 2019
    As you posted the answer up, I'm not entirely sure how I would have done it, but I think I would have thought as follows.

    Seven and eight is fifteen, carry the ten; two and four is six and one is seven: seventy-five.

    Be interesting to try it with two three-digit numbers.
    1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
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  • awavey
    awavey Posts: 2,368
    awavey wrote:
    or am I missing something obvious here

    There's no trick and nothing you're missing.
    It's just interesting that people have different thought processes to get the same answer.

    some have very complicated thought processes by the looks of it :lol:
  • pblakeney
    pblakeney Posts: 27,382
    awavey wrote:
    awavey wrote:
    or am I missing something obvious here

    There's no trick and nothing you're missing.
    It's just interesting that people have different thought processes to get the same answer.

    some have very complicated thought processes by the looks of it :lol:
    Thing is, everyone thinks their process is the simplest...
    The above may be fact, or fiction, I may be serious, I may be jesting.
    I am not sure. You have no chance.
    Veronese68 wrote:
    PB is the most sensible person on here.
  • Ben6899
    Ben6899 Posts: 9,686
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...
    Ben

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  • tailwindhome
    tailwindhome Posts: 19,439
    rjsterry wrote:
    As you posted the answer up

    Yeah. I gave the answer as I wanted it to be clear it wasn't a 'trick question' but should have left that out as it maybe skews your natural thought process.
    “New York has the haircuts, London has the trousers, but Belfast has the reason!
  • Pross
    Pross Posts: 43,479
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    Must be a Civil Engineer thing as I did similar but added on 50 and took off 2.
  • DeVlaeminck
    DeVlaeminck Posts: 9,107
    50 plus 27 minus 2
    [Castle Donington Ladies FC - going up in '22]
  • rick_chasey
    rick_chasey Posts: 75,660
    48 is two under 50 and 27 is two over 15 so cancel each other out - 25+50.

    Weird i know. I tend to see the differences between round numbers.
  • craigus89
    craigus89 Posts: 887
    I did...

    7+48 = 55
    55+20 =75

    Not sure why but I always seem to do things that way, get the smaller number to a round and then the rest is easy.
  • Ben6899
    Ben6899 Posts: 9,686
    Pross wrote:
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    Must be a Civil Engineer thing as I did similar but added on 50 and took off 2.

    Must be! :)
    Ben

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  • rjsterry
    rjsterry Posts: 29,690
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    My two primary school age children have been taught "number bonds" - memorising pairs of numbers that sum to each of the integers from 2 to 20, in much the same way as times tables. Possibly you have memorised that 27 + 48 = 75 through repetition, without realising it.
    1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
    Pinnacle Monzonite

    Part of the anti-growth coalition
  • Ben6899
    Ben6899 Posts: 9,686
    rjsterry wrote:
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    My two primary school age children have been taught "number bonds" - memorising pairs of numbers that sum to each of the integers from 2 to 20, in much the same way as times tables. Possibly you have memorised that 27 + 48 = 75 through repetition, without realising it.

    It's highly likely. I can't remember to buy milk, but remember various numbers without any issue.
    Ben

    Bikes: Donhou DSS4 Custom | Condor Italia RC | Gios Megalite | Dolan Preffisio | Giant Bowery '76
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    Flickr: https://www.flickr.com/photos/143173475@N05/
  • rick_chasey
    rick_chasey Posts: 75,660
    rjsterry wrote:
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    My two primary school age children have been taught "number bonds" - memorising pairs of numbers that sum to each of the integers from 2 to 20, in much the same way as times tables. Possibly you have memorised that 27 + 48 = 75 through repetition, without realising it.

    This is certainly how I see it.

    I end up half visualising them as shapes that tessellate. 2s match with 8s, 7s with 3s etc.
  • hopkinb
    hopkinb Posts: 7,129
    As per some of the first posters:

    20+40=60
    8+7=15
    60+15=75

    Columnar addition in my head I suppose.
  • Ben6899
    Ben6899 Posts: 9,686
    rjsterry wrote:
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    My two primary school age children have been taught "number bonds" - memorising pairs of numbers that sum to each of the integers from 2 to 20, in much the same way as times tables. Possibly you have memorised that 27 + 48 = 75 through repetition, without realising it.

    This is certainly how I see it.

    I end up half visualising them as shapes that tessellate. 2s match with 8s, 7s with 3s etc.

    This is the driver for how I said I would help someone figure it out. I certainly do this for larger numbers, but as rjsterry suggested... I work with numbers every day - down to mm and 3dp - so I think I simply memorise certain sums, subtractions and multiplications.

    Interesting thread, thanks to TWH for starting it off!
    Ben

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  • rick_chasey
    rick_chasey Posts: 75,660
    Fast and slow thinking, innit.
  • herb71
    herb71 Posts: 253
    I round up 48 to 50,

    50+27=77
    77-2 (the rounding difference).

    Not very elegant.
  • rjsterry
    rjsterry Posts: 29,690
    Ben6899 wrote:
    rjsterry wrote:
    Ben6899 wrote:
    This is interesting. I just thought "75" and not sure how I got there!

    If I had to help someone figure it out I would probably tell them to work out 30+48 and then knock off the three difference between 27 and 30. Or similar with 27+50...

    My two primary school age children have been taught "number bonds" - memorising pairs of numbers that sum to each of the integers from 2 to 20, in much the same way as times tables. Possibly you have memorised that 27 + 48 = 75 through repetition, without realising it.

    It's highly likely. I can't remember to buy milk, but remember various numbers without any issue.

    Repetition, innit. Darts players are very good at adding doubles and triples of 1-20, and subtracting these from 501.
    1985 Mercian King of Mercia - work in progress (Hah! Who am I kidding?)
    Pinnacle Monzonite

    Part of the anti-growth coalition
  • mfin
    mfin Posts: 6,729
    Ever so slightly different order.

    Upon looking immediately the first thing my brain sees the 7 and 8 and knows that's 15, the rest comes after that.

    7+8 =15
    40+20 = 60
    ...75

    But strangely, I looked at it and immediately thought 75 and all this that followed was just a double check.
  • pinno
    pinno Posts: 52,398
    48+22+5.
    seanoconn - gruagach craic!
  • robert88
    robert88 Posts: 2,696
    Found the biggest divisor of twenty added the remainders.