Because they are tables of the numbers that are the result of "times"-ing a number.
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Times tables
1182363544725906108712681449162101801119812216
No
None of the conventional times tables have 13 in them, because it is prime. The only times table that would have 13 and 39 in it would be the 13 times table!
They do not necessarily do so. It depends on the country and school. I learned them to 10 times but for tables up to 30!