Question

Chứng tỏ rằng abcd - ( a+b+c+d ) : 9 ( chia hết cho 9 )

Answer 1

Ta có:

abcd - (a + b + c + d)

= 1000a + 100b + 10c + d - a - b - c - d

= 999a + 99b + 9c

= 9.(111a + 11b + c) chia hết cho 9 (đpcm)

Answer 2

ta có

abcd-(a+b+c+d)

=1000a+100b+10c+d-a-b-c-d

=(1000a-a)+(100b-b)+(10c-c)+d

=999a+99b+9c+d

=9.111a+9.11b+9.c+d

=9.(111a+11b+c+d) chia hết cho9

Answer 3

k cho mk với nhé