That is just a simple transformation of algebraic expressions.
Chinese one is practical. Indian one is not. No help to Arithmetics on paper
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In those remote, almost forgotten years, a Chinese boy added the results of Nine Nine multiply song by singing in heart . Guess what, he got 5555, the correct one. The dying one still remembers this number.
Any others here still remember the other song: Nine Nine dividing???
2 meets 1 you get 5;
2 meets 2 you get 10;
3 meets 1 you get 31;
3 meets 2 you get 62;
.......
The Chinese boy used it to do divisions too and got quicker and quacking on abacus.
The dying one miss those years. The dying one miss this life.