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       # MATH introduce subtraction
[hear] (intro -);

[hear] (= 00 / - 0110 0110);

[hear] (= 011110 / - 0111110 010);

[hear] (= 0110 / - 0110 00);

[hear] (= 00 / - 011110 011110);

[hear] (= 01110 / - 011110 010);

[hear] (= 010 / - 01110 0110);

[hear] (= 00 / - 00 00);

[hear] (= 011110 / - 011110 00);

[hear] (= 0110 / - 01110 010);

[hear] (= 011110 / - 011110 00);