Question

Marvin counts six $5 bills. write each value that he counts. what pattern do you see in the one digits of the values he counts?

Answer 1

Answer: If the number of bills counted is odd, the ones digit is 5; if the number of bills is even, the ones digit is 0.

Explanation

1) Simulate the counting of the bills:

number of bills counted          value              ones digit

1                                             5                         5

2                                             5 + 5 = 10           0

3                                             10 + 5 = 15         5

4                                             15 + 5 = 20         0

5                                              20 + 5 = 25        5

6                                              25 + 5 = 30        0

2) Pattern: you can see that the ones digit alreternate: 5, 0, 5, 0, 5, 0, ...

If the number of bills counted is odd the ones digit is 5, if the number of bills is even the ones digit is 0.