PPT Slide
In 1,200 years:
1. A total of 300 years are divisible by 4
2. Leaving a total of 900 years not divisible
by 4
3. 12 century-years are possible leap years,
but . . .
4. Only 3 century years out of 12 are
divisible by 400 (e.g., {400, 800, 1200},
{1600, 2000, 2400}, etc.); so, only 3
century years are actual leap years.