=2001*1=2001
【2001×(4.3×87+4.4)】/(4.4×87-4.3)=【2001×(4.3×87+4.4)】/((4.3+0.1)×87-4.3)==【2001×(4.3×87+4.4)】/((4.3×87+8.7-4.3)==【2001×(4.3×87+4.4)】/(4.3×87+4.4)=2001
