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The trick to this question is to realize that you can tell a number is divisible by nine by observing whether the sum of it's digits is divisible by nine.
For example, we know that the number 25731 is divisible by nine, because 2 + 5 + 7 + 3 + 1 = 18, and 18 is divisible by nine.
So in this case, what we want is a value for "A" in which 3 + A + A + 1, or 2A + 4, is divisible by 9. "A" also has to be less than ten (as we're dealing with a specific digit). That leaves us with only one possible digit, 7. 3 + 7, + 7 + 1 = 18, and 18 is indeed divisible by nine, so we know that 3771 is also divisible by nine.
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What is the converse inverse and contrapositive If every digit of a number is divisible by 3 then the number is divisible by 3?
Converse:If a number is divisible by 3, then every number of a digit is divisible by three. Inverse: If every digit of a number is not divisible by 3 then the number is not divisible by 3? Contrapositive:If a number is not divisible by 3, then every number of a digit is not divisible by three.
How many 3 digit number are divisible by 5?
There are 180 3-digit numbers divisible by five.
The number 3456 is divisible by which single-digit numbers?
3456 is divisible by the single digit numbers 1,2,3,4,6,8,9
What is the rule for a number that is divisible by 4?
If the last two digits are divisible by 4 then the number is divisible by 4. Thus, if the tens digit is even and the units digit is 0 or 4 or 8 OR if the tens digit is odd and the units digit is 2 or 6 then the number is divisible by 4.
How many 3 digit numbers are divisible by 6 in all?
There are 151 3-digit numbers that are divisible by 6.
