From Grok:

To calculate Donald Trump's age when he took office on January 20, 2017:

Date of Birth: June 14, 1946

Year: 2016 - 1946 = 70 years

Months: From June to January is 7 months.

Days in January 2017 before taking office:

January has 31 days, and he took office on the 20th, so:

14 days (from January 1 to January 14) + 20 days in January = 20 days.

Therefore, when Donald Trump took office on January 20, 2017:

Years: 70 years

Months: 7 months

Days: 6 days (since January 14th to January 20th is 6 days)

So, he was 70 years, 7 months, and 6 days old when he took office.