Hi! My name is Matthew
Usage of digit sum:
The number is divisible by 3, when its digit sum is divisible 3.
The number is divisible by 9, when its digit sum is divisible 9.
Digit sum is the sum of all digits of the integer. We write DS(n).
For example: DS(483) = 4 + 8 + 3 = 15.
How much is DS(981)?
DS(981) = ________.
DS(981) = 18.
7th grade, Digit sum8th grade, Digit sum
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