help!

For students upto class 5 (age upto 12)
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samiul_samin
Posts: 999
Joined: Sat Dec 09, 2017 1:32 pm

Re: help!

Unread post by samiul_samin » Tue Feb 20, 2018 7:04 pm

M. M. Fahad Joy wrote:
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.
Yes,I also believe it.Detailed Solution

Think about the sum of these numbers
$000$
$001$
$002$
$003$
$004$
$005$
$006$
.
.
.
.
.
$600$
.
.
.
.
$998$
$999$

The sum is
$(1+2+3+4+5+6+7+8+9)×(100+100+100)=45 ×300=13500$... ... ...($1$)

Now as a same manner think about them
$1000$
$1001$
$1002$
$1003$
$1004$
$1005$
$1006$
$1007$
$1008$
$1009$
$1010$
.
.
.
$1699$
.
.
.
$1998$
$1999$
The sum of these numbers $13500+1000=14500$... ... ...($2$)

Now count the numbers from 2000 to 2015,you will get
$(16×2)+1+2+3+4+5+6+7+8+9+(1×6)+1+2+3+4+5=98$... ... ...($3$)

($1$)+($2$ )+($3$)$=13500+14500+98=28098$



I hope it is clear to you now.If not feel free to question.I will not get bothered

User avatar
M. M. Fahad Joy
Posts: 120
Joined: Sun Jan 28, 2018 11:43 pm
Location: Bhulta, Rupganj, Narayanganj
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Re: help!

Unread post by M. M. Fahad Joy » Tue Feb 20, 2018 9:58 pm

samiul_samin wrote:
Tue Feb 20, 2018 7:04 pm
M. M. Fahad Joy wrote:
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.
Yes,I also believe it.Detailed Solution

Think about the sum of these numbers
$000$
$001$
$002$
$003$
$004$
$005$
$006$
.
.
.
.
.
$600$
.
.
.
.
$998$
$999$

The sum is
$(1+2+3+4+5+6+7+8+9)×(100+100+100)=45 ×300=13500$... ... ...($1$)

Now as a same manner think about them
$1000$
$1001$
$1002$
$1003$
$1004$
$1005$
$1006$
$1007$
$1008$
$1009$
$1010$
.
.
.
$1699$
.
.
.
$1998$
$1999$
The sum of these numbers $13500+1000=14500$... ... ...($2$)

Now count the numbers from 2000 to 2015,you will get
$(16×2)+1+2+3+4+5+6+7+8+9+(1×6)+1+2+3+4+5=98$... ... ...($3$)

($1$)+($2$ )+($3$)$=13500+14500+98=28098$



I hope it is clear to you now.If not feel free to question.I will not get bothered

Thanks brother. You have great minds. You have solved all my problems of digits. But it has taken 4 hours from me.Image
Math is the main inspiration of my life.

User avatar
samiul_samin
Posts: 999
Joined: Sat Dec 09, 2017 1:32 pm

Re: help!

Unread post by samiul_samin » Tue Feb 20, 2018 10:02 pm

Ok,No problem.

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