【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