how many 2-digit even numbers are there ? 

How many 4-digit whole numbers, whose sum of all its digits is 35, are even?
Answer:  number(s).(dịch+cách làm)

How many three-digit numbers are exactly 19 more than a two-digit number?
Answer: ............. numbers.

How many three-digit numbers are exactly 19 more than a two-digit number?
Answer: ............. numbers.

How many natural numbers having three digits such thatthe tens digit squared equals the product of other digits and the differencebetween that number and its reversed order is 495?
Answer: There are numbers.

How many natural numbers having three digits such that the tens digit squared equals the product of other digits and the difference between that number and its reversed order is 495?
Answer: There are numbers.

How many natural numbers having three digits such thatthe tens digit squared equals the product of other digits and the differencebetween that number and its reversed order is 495?
Answer: There are  numbers.

Exercise 7. Choose 2 numbers, without repetition, from 0, 3, 5, 6, 9 to form a 2-digit number. How many numbers with a digit “9” are there?

A. 6        B. 9            C. 7           D. 8

How many single digit numbers are there?
Answer:  numbers.