C462 Coprimadione

Comprehension, Wan Ri Ming, just like how you know the principle of one plus one, of course you have to be equal to two, then you can also use this method to know all the additions, one plus one, one plus two, one plus three, two plus one, two plus two, two plus three, double-digit additions, multi-digit additions, no matter how the numbers add up, it doesn't change at all, but when you