Question

How many of the natural numbers can be formed from the digit 2,3,5,7,9? How many of them are odd? Solve the sum

Answer 1

Answer:

For each such choice, you can use any of the other four digits as the tens digit. Therefore, there are 4⋅2=8 two-digit even numbers that can be formed using only the digits 3,4,5,6,7.You mean how many possible 7 digit numbers using 0-9. 10^7 or 10 million, or 10,000,000 (one followed by seven zeroes) which is a set that includes 0000000.