Multiple of 5.
5n
Idea: A “multiple of 5” means a number you get by multiplying 5 with some whole number or negative whole number.
Step 1: See some examples
(5 imes 1 = 5)
(5 imes 2 = 10)
(5 imes 3 = 15)
Also works for zero and negatives:
(5 imes 0 = 0)
(5 imes (-2) = -10)
Step 2: Write the general form
Let the multiplying number be (n). Then the number is (5 imes n).
Step 3: Say what (n) can be
(n) can be any integer (… (-2), (-1), (0), (1), (2), …).
Conclusion
Every multiple of 5 can be written as (5n), where (n) is an integer.