13
23
all the 30's
43
53 and so on
The numbers from 1 to 39 include both single-digit and double-digit numbers. There are 9 single-digit numbers (1 to 9) and 30 double-digit numbers (10 to 39). Therefore, the total number of digits is 9 (from single-digit numbers) + 60 (from double-digit numbers, as each has 2 digits) = 69 digits in total.
2893 digits in all, made up as follows: 9 1-digit numbers (1 to 9) = 1*9 = 9 digits 90 2-digit numbers (10 to 99) = 2*90 = 180 digits 900 3-digit numbers (100 to 999) = 3*900 = 270 digit 1 4-digit number (1000) = 4*1 = 4 digits
2
There are 9 possible numbers for the first digit (one of {1, 2, ..., 9}); with 9 possible digits for the second digit (one of {0, 1, 2, ..., 9} which is not the first digit)); with 8 possible digits for the third digit (one of {0, 1, 2, ..., 9} less the 2 digits already chosen); This there are 9 × 9 × 8 = 648 such numbers.
There are 238 - 1 = 237 numbers between 1 and 238. To find the number of digits, we need to consider the range of numbers from 1 to 9 (1-digit numbers), 10 to 99 (2-digit numbers), and 100 to 238 (3-digit numbers). There are 9 one-digit numbers, 90 two-digit numbers, and 139 three-digit numbers between 1 and 238, totaling 9 + 90 + 139 = 238 digits.
6
Any number that has 4 or 5 digits. A digit in a number is one number place. 1 has 1 digit, 11 has 2 digits, 111 has 3 digits, and so on.
In the numbers 1-9 each number has 1 digit and there are 9 of them, so that's 9.In 10-99 each number has 2 digits, and there are 90 of them: 2x90 = 180There are 900 three digit numbers [100 through 999]: 2700 digits.There are 9000 four digit numbers: 36000 digits.90,000 numbers with five digits: 450,000 digits.900,000 numbers with six digits: 5,400,000 digits.Then 1 number with seven digits: 7 digits.Add them up and you have 5,888,896 digits.
To form a three-digit even number with different digits using the digits 0, 1, and 2, the last digit must be even, which can only be 0 or 2. If the last digit is 0, the first digit can be either 1 or 2 (2 options), and the middle digit will take the remaining digit (1 option). This gives us 2 valid numbers: 120 and 210. If the last digit is 2, the first digit can only be 1 (since it cannot be 0), and the middle digit must be 0. This gives us 1 valid number: 102. In total, there are 3 different three-digit even numbers: 120, 210, and 102.
162
There are 34 = 81 numbers.
First 9 pages = 9 digit. That leaves 142 digits. @ 2 digit per page, that is 142/2 = 71 pages with 2-digit numbers. So, 9 pages with 1-digit numbers + 71 pages with 2-digit numbers = 80 pages.