This can be solved by looking at each set of digit lengths. From 1 through 9, it's obvious there are 9 digits. From 10 through 99, there are 2 digits for each of the 90 numbers, so that makes 90*2=180 digits. Next, from 100 to 400, there are 401 numbers with 3 digits each, making another 401*3=1,203 digits. So the final answer is 9+180+1,203 = 1,392 digits.
1 in 1 and 3 in 200.
1 to 9 have 1 digit and 10 to 99 have 2 digits so (9 x 1) + (90 x 2) = 189
1,2,3,4 1+2+3+4=10 4 times 3 times 2 times 1 =24 24 counting numbers
10
2,401
121
I believe here are 51 such numbers.
There are 2700 digits.
There are 400. Assuming the number must be at least 10,000, then: In a 5 digit palindrome, the first and last digits must be the same, and the second and fourth digits must be the same; and: For the first and last digit there is a choice of 4 digits {2, 4, 6, 8}; For each of these there is a choice of 10 digits {0, 1, ..., 9} for the second and fourth digits; For each of the above choices these is a choice of 10 digits {0, 1, ..., 9} for the third digit; Making 4 x 10 x 10 = 400 possible even 5 digit palindromes.
400 ÷ 1/4 = 400 × 4/1 = 1600
Infinity is not a number, but a concept representing something that is unbounded or limitless. As such, it does not have a specific number of digits. In mathematics, infinity is often used to describe a quantity that is larger than any finite number. Therefore, infinity cannot be quantified in terms of digits.
400,000,000
1
1
630 digits.
1 digit
1