For @7ty8lx How I calculated this: In decimal: 10x10x10=1,000 In double factorial (even): 6x4x2=48 48 is 1000 in base double factorial (even), so… How to make 2000: 48x2=96 Since you can’t have 1 as 10 in double factorial (odd), you can have 2 as 10 in double factorial even so… How to make 2020: 96+4=100
