gọi các số cần tìm có dạng abcd0. có 9 cách chọn a
có 8 cách chọn b
có 7 cách chọn c
có 6 cách chọn d
vậy số các số có 5 chữ số khác nhau chia hết cho cả 2 và 5 là: 9 x 8x 7x 6
Các số chia hết cho 2 và 5 phải có số tận cùng tận cùng là :0
Ta có dãy 10000,10010, ... 90090.
Có số các số có 5 chữ số chia hết cho 2 và 5 là :
( 90090 - 10000 ) : 10 + 1 = 8010 ( số )
Đáp số : 8010 số
9 cách chọn hàng chục nghìn
8 cách chọn hàng nghìn
7 cách chọn hàng trăm
6 cách chọn hàng chục
và 1 cách chọn hàng đơn vị
Số các số:
9*8*7*6*1=3024
tớ thử rồi
lqwertyuiopdasghfkjxczbvnm
ewqrtypdasghfkljcxzbvnm
qewrtyoipdsaghflk
đứa nào mà chọn 8010 là đứa ngu 3024 mới đúng
tất cả đều sai tôi là giáo viên dạy toán quốc gia không phải đáp án là 3024 mà cũng chẳng phải là 8010
b,j hgfhmfghgfkhjdkkgxfhlckhgjhkjhijghkjhkjgkhj
llllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllllll
Những số này có dạng abcd0
a có 9 cách chọn
b có 8 cách chọn
c có 7 cách chọn
d có 6 cách chọn
Theo quy tắc nhân, ta có: 9 x 8 x 7 x 6 x 1 = 3024
