5 items are filed under this topic.
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How many numbers from the set have the sum of its digits equal to 2? |
2019-10-24 |
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From Marcel:
Hello. My question is the following: Given the set {1,2...........10exp2019}, how many numbers from the set have the sum of its digits equal to 2?
I got some of them : 2 20 200 2000 20000 .......2. 10exp2018 11 110 1100 11000 110000....101 1010 10100 101000 1010000....10011 10010 100100 1001000 1010000.....10001 100010 1000100 10001000,,,,,,100001 1000010 10000100.......
My problem is that I have difficulty in finding a strategy to obtain the exact quantity of numbers.
Please help me, thanks
Answered by Penny Nom. |
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The sum of the digits of two-digit number is 9 |
2008-07-01 |
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From Audrey:
the sum of the digits of two-digit number is 9. if the digits are reversed, the new number if 63 greater than the original number. find the number.
Answered by Penny Nom. |
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111...111 * 2003 |
2008-06-23 |
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From Peggy:
Number a = 111...111 formed by 2003 1's. Find the sum of the digits of the number 2003 * a.
Answered by Penny Nom. |
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The sum of the digits of a number |
2008-06-23 |
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From Ben:
Question: Using mathematical induction, prove that if the sum of the digits of a number is divisible by three, then the number itself is also divisible by 3.
Answered by Penny Nom. |
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The sum of the digits of 2^100 |
2005-06-11 |
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From Richard:
The sum of the digits was calculated for the number 2100, then the sum of the digits was calculated for the resulting number and so on, until a single digit is left.
Answered by Penny Nom. |
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