Question

1.998*199919991999-1.999*199819981998 简便计算

五年级简便计算。 急急急急急急急急急急急急！！快啊

Answer 1

1.998 × 199919991999 - 1.999 × 199819981998
= 1998 × 1999 × 0.001 × 100010001 - 1999 × 1998 × 0.001 × 100010001
= （1998 - 1998）× 1999 × 0.001 × 100010001
= 0 × 1999 × 0.001 × 100010001
= 0

Answer 2

1.998*199919991999
=1.998*(199900000000+19990000+1999)
1.999*199819981998
=1.999*(199800000000+19980000+1998)
相减=0

Answer 3

1.998×199919991999－1.999×199819981998
＝1998÷1000×1999×100010001－1999÷1000×1998×100010001
＝0

Answer 4

1.998*199919991999-1.999*199819981998
=1.988*1.999*(100010001000)-1.988*1.999*(100010001000)
=0

Answer 5

原式=1998*1999*10001000-1999*1998*10001000=1-1=0