Will You Sign This Open Letter To Show...
Society & Culture0 min ago
I was buying an item in the grocers this morning which was marked reduced by 25%. The original price was £2.80.
The lady went to the calculator on her phone to do the maths.
I told her the answer and when she'd checked she said you're right.
Do the schools not teach mental arithmetic any more?
I'm hopeless at mental arithmetic. My brain seems only hard-wired for visual things. If I had to do that sum, I would think a quarter of 2 pounds is 50p. & a quarter of 80p is 20p which equals 70p. Take that from £2.80. makes £2.10.
Quite a bit of effort for me, so I'd reach for the pocket calculator any time.
How would you do it?
There is a story (probably apocryphal) that when Einstein was a child in school, the teacher wanted to leave the classroom & wished to give them something to do while she was out, so she said, "Add up all the numbers from 1 to 100.
Before she reached the door Einstein put up his hand & gave the answer.
What he had seen, & something I can relate to, is that if you visualise all the numbers as laid out in a row & take the first and the last they add up to 101, then take the second and the penultimate & they also add up to 101 keep going and he saw you could pair up the numbers so that each pair adds up to 101, as follows:
1 + 100 = 101
2 + 99 = 101
3 + 98 = 101
…
48 + 53 = 101
49 + 52 = 101
50 + 51 = 101
Thinking about it this way, it becomes fairly obvious that the answer would be 50 x 101, which becomes quite doable in many people’s heads as 5,050. - Even mine.
😃
I've heard that story attributed to Gauss.
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Sandy - I think Ican better all of these. The new chap next door (29, single, - doesn't speak, works from home on computers) put a note through our door asking for our share of payment for the electricity for the running of the klargester for the septic tank. We knew a few quid were in order per month, but he'd queried the exact amount and OH had asked him to send us a bill.
We went round and asked... £3.00 per month he reckoned. We're not arguing, we thought about the same. Anyway, he said thatwe hadn't paid for 8 months (we didn't know how much he wanted) so I said, "OK, 8 threes is 24 - we owe you 20 quid." He looked at me, baffled. Turns out he's an accountant!!
I told him that it was easy to see that he hadn't been educated in the 1950s. :)