
hghfghfgh 26/03/2017 at 20:16
At the begining, there are 1974/2=987 odd numbers. When we replace two numbers a and b by a number either a + b or a  b, we see that:
+ if a odd and b even, or a even and b odd then a + b or a  b is still odd
+ if a and b are both even then a + b or a b is still even
+ If a and are both odd then a + b or a  b is even
So the number of odd after each such replacement operation is stay the same or deacresed by two. At the begining, there is 987 odd numbers (987 is odd) and the odd number left must be odd too. So at the final, only one number left, it must be odd number, it is not 0. (because 0 is even).

Faded 19/01 at 14:52
At the begining, there are 1974/2=987 odd numbers. When we replace two numbers a and b by a number either a + b or a  b, we see that:
+ if a odd and b even, or a even and b odd then a + b or a  b is still odd
+ if a and b are both even then a + b or a b is still even
+ If a and are both odd then a + b or a  b is even
So the number of odd after each such replacement operation is stay the same or deacresed by two. At the begining, there is 987 odd numbers (987 is odd) and the odd number left must be odd too. So at the final, only one number left, it must be odd number, it is not 0. (because 0 is even). [haha]

An Duong 10/03/2017 at 14:14
At the begining, there are 1974/2=987 odd numbers. When we replace two numbers a and b by a number either a + b or a  b, we see that:
+ if a odd and b even, or a even and b odd then a + b or a  b is still odd
+ if a and b are both even then a + b or a b is still even
+ If a and are both odd then a + b or a  b is even
So the number of odd after each such replacement operation is stay the same or deacresed by two. At the begining, there is 987 odd numbers (987 is odd) and the odd number left must be odd too. So at the final, only one number left, it must be odd number, it is not 0. (because 0 is even).

xicor 24/08/2017 at 10:39
coppy là gian nghe

Nguyễn Tiến Dũng 29/08/2017 at 13:03
At the begining, there are 1974/2=987 odd numbers. When we replace two numbers a and b by a number either a + b or a  b, we see that:
+ if a odd and b even, or a even and b odd then a + b or a  b is still odd
+ if a and b are both even then a + b or a b is still even
+ If a and are both odd then a + b or a  b is even
So the number of odd after each such replacement operation is stay the same or deacresed by two. At the begining, there is 987 odd numbers (987 is odd) and the odd number left must be odd too. So at the final, only one number left, it must be odd number, it is not 0. (because 0 is even).

Help you solve math 28/08/2017 at 20:46
We are copy

Help you solve math 13/08/2017 at 08:52
Copy nhau à