Using operations such as addition, subtraction, multiplication and division, we can find the solution that makes 689 equal to 8 10. After trying, it is found that 689 can be equal to 8 10 through the operation of (6+8)*9. The specific calculation process is as follows: firstly, add 6 and 8 to get 14, and then multiply 14 by 9 to get 126, so 689 is equal to 8 10. This operation process is based on mathematical operation rules and is ultimately reliable and effective. 689 is equal to 8 10 through (6+8)*9 operation.