If the sum of the digits in a number is a ____ of 3, then the number is divisible by 3.
multiple
Divisibility rule for 3 (easy steps)
Why this works (in small steps)
Let the number be \(N\) and the sum of its digits be \(S\).
Check if \(S\) can be written as:
\(S = 3 \times k\) for some whole number \(k\).
If yes, then:
\(N\) is divisible by \(3\).
Example 1
\(N = 123\)
Add digits: \(1 + 2 + 3\)
\(= 6\)
Check multiple of 3: \(6 = 3 \times 2\) → yes
So, \(123\) is divisible by \(3\).
Example 2 (not divisible)
\(N = 124\)
Add digits: \(1 + 2 + 4\)
\(= 7\)
\(7\) is not a multiple of \(3\).
So, \(124\) is not divisible by \(3\).
Conclusion: The blank is multiple.