A simplest fraction, if the numerator plus 1, the fraction is 23; if the denominator plus 1, the fraction is 12, the fraction is 23______ ．

A simplest fraction, if the numerator plus 1, the fraction is 23; if the denominator plus 1, the fraction is 12, the fraction is 23______ ．

When the denominator is 3, 13's denominator plus 1, the score is 14, which is not in line with the meaning of the question; when the denominator is 6, 23 = 46, numerator minus 1 is 36, which is not the simplest score, which is not in line with the meaning of the question; when the denominator is 9, 23 = 69, numerator minus 1 is 59, denominator plus 1, the score is 510 = 12, which is in line with the meaning of the question