Answer: 6
Step-by-step explanation: To determine the mode:
1. Count the frequency of each digit in the number:
- The digit 6 appears 4 times.
- The digit 8 appears 2 times.
- The digit 9 appears 2 times.
2. Since the digit 6 appears the most frequently (4 times), the mode of the given number is 6.
Therefore, the mode of the number 88669686 is 6.