How many minutes are there in a decade?

By my reckoning, 60 (minutes in 1 hour) x 24 (hours in a day) x 365.25 (days in a year, allowing for leap year) x10, so that's 60 x 24 x 365.25 x10 =5259600.
Willing to sit corrected.

5,256,000 would be 10 years at 365 days a year. It depends what years to get a correct answer.

Suppose it is 2000-2009. 2000, 2004, and 2008 are leap years. That's an additional day 3 times. Total would be 5,260,320.

If it was 2001-2010, you would have 2 leap days. Total of 5,258,880 minutes.

Keep in mind every 400 years there is no leap day on years ending in 00 that begin with a non-multiple of 4, such as the years 1800, 1400, 1000, 600...

If the years are 1797-1806, you would have only 1 leap day in those years. Total of 5,257,440 minutes.