Arcity 🇵🇸🇺🇦

It depends on the convention whether enumerating starts with the zeroth or first. In programming for example indices commonly start at zero. And the numbering of floors is another example of where starting at zero is quite common.

Cardinal numerals refer to amount (one, two, three) and ordinal refers to a position in a sequence (first, second, third). So your example is ordinal not cardinal.

Both are ordinal. One just start with 0 and the other with 1.

rm doesn’t remove memory in RAM