- Có bao nhiêu số có 4 chữ số lập được chỉ từ các chữ số 0 và 1 ?
Bài làm :
Có 1 cách chọn chữ số hàng nghìn ; 2 cách chọn chữ số hàng trăm; hai cách chọn chữ số hàng chục; 2 cách chọn chữ số hàng đơn vị.
Tổng cộng :
1 x 2 x 2 x 2 = 8 ( số )
Vậy ...
How many 4 - digit numbers can you make by using only 0 and 1?
Answer:
how many 3- distinct digit numbers can you make from 0, 2, 5, 6 and 8
24 4- digit number can be formed by using 1,3,5 and 7, with each digit being used exactly one each time. Find the average of these 24 numbers?
choose 3 digits from 1, 3, 4, 5, 9 to form 3-digit numbers. how many number(s) that can be divisible by 5 is / are there?
choose 3 digits from 1, 3, 4, 5, 9 to form 3-digit numbers. how many number(s) that can be divisible by 5 is / are there?
How many four -digit -numbers have 1 as their second digit and 5 as their last digit ?
Question 9:
If we write all of the whole numbers from 10 through 99 and cross out any number in which the first or second digit is divisible by 2 (for example, 41 is crossed out as 4 is divisible by 2 and 36 is crossed out as 6 is divisible by 2), how many numbers are crossed out?
Answer: numbers.
Given 4 digits: 4, 6, 2, 0.
What is the difference of the largest and the smallest 4-digit numbers that can be formed from these digits. Use each digit only ones.
Answer: The difference is
How many 2-digit numbers do not include digit 0
