①:[14×15×48]÷[7×3×16]
=(2*7*3*5*3*16)÷(7*3*16)
=2*5*3=30
②33333×66666
==33333*3*22222
=99999*22222
=(100000-1)*22222
=2222200000-22222
=2222177778
③1997×19981998-1998×19971997 =(1997*1998)*(10001-10001)=0
④[+25]×[-4]=-100
⑤0.25×32×0.125=0.25*4*8*0.125=1*1=1