Question

Сколько существует чётных натуральных чисел,меньших 1000, у которых количество цифр чётно?

Answer 1

Меньше 1000 значит числа 3,2,1 значные.3 значные и 1 значные неподойдут потомушто сумма цифр должна быть четным.Количество 2 значных четных чисел 45

Answer 2

Number of Even Natural Numbers with Even Number of Digits Less Than 1000

The number of even natural numbers with an even number of digits less than 1000 can be calculated by considering the number of even digits in each place value.

Calculation: - For the units place: There are 5 even digits (0, 2, 4, 6, 8) and 5 odd digits (1, 3, 5, 7, 9). Therefore, the number of even digits in the units place is 5. - For the tens place: There are 10 digits (0-9), and half of them are even. Therefore, the number of even digits in the tens place is 5. - For the hundreds place: There are 10 digits (0-9), and half of them are even. Therefore, the number of even digits in the hundreds place is 5.

Total Calculation: - Total even numbers with even number of digits less than 1000 = (5 * 5 * 5) = 125

Conclusion: - Therefore, there are 125 even natural numbers with an even number of digits less than 1000.