2.5的2009次方乘以2再乘以负0.9的2010次方
=(2.8938593686933054245877095427272e+799)*2*(1.0652314326662498374173869631581e-92)
=(2.8938593686933054245877095427272e+799)*2.1304628653324996748347739263161e-92
=6.1652599224956380802952613232552e+707