A mathematical question for you

[ChimpMaster]

My special number has a 9 in the units column. If I remove the 9 from the units column and place it at the left hand end of the number, but leave all the other digits unchanged, I get a new number. This new number is four times my special number. What is my special number?

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So the question above is from an 11+ grammar school entry exam. I've worked out the answer but not without some pain and guesswork thrown in for good measure. I just can't imagine how my kid or any 10 year is supposed to work it out!

[filthy1980]

Feck I'm stumped

I'm going to have to pay for a tutor aren't I?

got 3 of the buggers too

[scooterscot]

Scientific notation notwithstanding, what column is the units column?

[BrilloPad]

Scientific notation notwithstanding, what column is the units column?

And here we have today's winner of the sasguru cretinism prize.

[BrilloPad]

I am pleased that question did not come up the year I did 11+. I would have failed!

declare @a int
declare @b float

select @a=1
while @a < 100000
begin
select @a=@a+1
select @b=convert(float, '9'+convert(varchar(10), @a))/convert(float,convert(varchar(10), @a) + '9')
if (@b > 3.9999) and (@b<4.0001)
select @a, @b
end

[filthy1980]

Scientific notation notwithstanding, what column is the units column?

Thousands Hundreds Ten Units

is how I remember it

(and what I was trying to teach my daughter but her teachers teach them a different method that I didn't get)

[BrilloPad]

Thousands Hundreds Ten Units

is how I remember it

(and what I was trying to teach my daughter but her teachers teach them a different method that I didn't get)

I thought it was a castrated male?

[NotAllThere]

Easy

(n digits)9
x 4
9(n-1 digits)6


So the hundred's digit is 6. Continue to get 230769

[scooterscot]

Now tell me where in the working world this will be used.

[scooterscot]

Thousands Hundreds Ten Units

is how I remember it

(and what I was trying to teach my daughter but her teachers teach them a different method that I didn't get)

Obviously, just it wasnae specific.