Question

tinh nhanh (tong day so ) : 

1999 - 2000 + 2999 - 3000 + 3999 - 4000 + 4999 - 5000 + 5999 - 1000 

Answer 1

1999 - 2000 + 2999 - 3000 + 3999 - 4000 + 4999 - 5000 + 5999 - 1000 

=(1999-2000)+(2999-3000)+(3999-4000)+(4999-5000)+(5999-1000)

=1+(-1)+(-1)+(-1)+4999

=1x4+4999

=4+4999

=4999-4

=4995

tk nha

Answer 2

=4995

k cho mik nhe

Answer 3

cac ban chinh bay cach giai ra nhe . day la tinh nhanh ma .