help!

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ahsaf
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help!

Unread post by ahsaf » Wed Jan 21, 2015 9:38 pm

what is the sum of the digits from 1 to 2015 ?
Ex. sum of the digits from 19 to 21 is: 1+9+2+0+2+1=15.

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ahsaf
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Re: help!

Unread post by ahsaf » Sat Feb 07, 2015 10:23 pm

can't anyone find the answer :o i cannot do it so i posted it.
N:B:logic and reason must be given. :!:
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tanmoy
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Re: help!

Unread post by tanmoy » Sat Feb 07, 2015 10:49 pm

I am giving you the process of solving it.I hope you will solve it own.
We want to count the sum of the digits of the number $1234567891011.........2015$.See that the sum of the digits from $1$ to $9$ is $45$.Now,the sum of the digits from $10$ to $19$ is $10\times1+45=55$.In this process you can count the total sum.
$\text{Another way}:$
Find the number of $1's$,number of $2's$...........number of $9's$ from $1$ to $2015$.
"Questions we can't answer are far better than answers we can't question"

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Raiyan Jamil
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Re: help!

Unread post by Raiyan Jamil » Mon Feb 16, 2015 10:12 pm

This is the 7th question of junior category Dhaka 2015. The ans is 28098. :D
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M. M. Fahad Joy
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Re: help!

Unread post by M. M. Fahad Joy » Tue Feb 20, 2018 11:07 am

Raiyan Jamil wrote:
Mon Feb 16, 2015 10:12 pm
This is the 7th question of junior category Dhaka 2015. The ans is 28098. :D

Why? the answer is 26600.
Math is the main inspiration of my life.

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samiul_samin
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Re: help!

Unread post by samiul_samin » Tue Feb 20, 2018 2:25 pm

M. M. Fahad Joy wrote:
Tue Feb 20, 2018 11:07 am
Raiyan Jamil wrote:
Mon Feb 16, 2015 10:12 pm
This is the 7th question of junior category Dhaka 2015. The ans is 28098. :D

Why? the answer is 26600.
No,the correct answer is $\fbox {28098}$.Calculate again ,you will get this number.

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M. M. Fahad Joy
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Re: help!

Unread post by M. M. Fahad Joy » Tue Feb 20, 2018 4:40 pm

samiul_samin wrote:
Tue Feb 20, 2018 2:25 pm
M. M. Fahad Joy wrote:
Tue Feb 20, 2018 11:07 am
Raiyan Jamil wrote:
Mon Feb 16, 2015 10:12 pm
This is the 7th question of junior category Dhaka 2015. The ans is 28098. :D

Why? the answer is 26600.
No,the correct answer is $\fbox {28098}$.Calculate again ,you will get this number.
Eta kivabe calculate korbo? Sutro ta bole diben?
Math is the main inspiration of my life.

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samiul_samin
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Re: help!

Unread post by samiul_samin » Tue Feb 20, 2018 4:48 pm

If you tell Bangla then use Avro.It is easy.
$(45×20×20)+(45×200)+1000+32+15+45=28098$
Last edited by samiul_samin on Tue Feb 20, 2018 6:34 pm, edited 1 time in total.

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M. M. Fahad Joy
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Re: help!

Unread post by M. M. Fahad Joy » Tue Feb 20, 2018 5:32 pm

বুঝলাম না:
(১) আপনার সূত্র
(২) একবার বলেন 28092 এবং আরেকবার 28098
Math is the main inspiration of my life.

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M. M. Fahad Joy
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Re: help!

Unread post by M. M. Fahad Joy » Tue Feb 20, 2018 5:44 pm

The main object of this forum is to make our students interested in maths. So we should not be bothered but helping each other.
Math is the main inspiration of my life.

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