
### Instruction: help me answer this question How many 5-digit telephone numbers can be constructed using the digits 0 to 9 if each number starts with 67 and no digit appears more than once?, think step by step
### Assistant: To find the total number of 5-digit telephone numbers, we need to find the number of possible digits for each place (excluding the ones already taken) and multiply them together. Here, the number of possible digits for the third place is 8, for the fourth place is 7 and for the fifth place is 6. , The answer is 336
