(20又9/4+12.25-31又30/1)÷299+9(13又9/1-12.25)×1又31/5
=(9/184+4/49-30/931)×299/1+9(9/118-4/49)×31/36
=[(9×20)/(184×20)+(4×45)/(49×45)-(30×6)/(931×6)]×299/1+9[(9×4)/(118×4)-(4×9)/(49×9)]×31/36
=(180/3680+180/2205-180/5586)×299/1+9(36/472-36/441)×31/36
=180/(3680+2205-5586)×299/1+9×36/(472-441)×31/36
=180/299×299/1+9×36/31×31/36
=180/1+9
=9又180/1
最后结果等于9又180分之1