Any number may be added
Highest 2-digit number = 99 Highest 1-digit number = 9 Highest possible sum from 2, 2-digit numbers = 198 Highest possible sum from 2, 1-digit numbers = 18
6
99 is not a prime because it can be divisible by 3 and 33
The highest two-digit prime number is 97. Out of that group, the highest (and only) prime number is 71.
89.
It is a table of numbers that are added and the first digit is displayed but if the answer of the 2 number when added is more than 1 digit, you add them again till it reaches a 1 digit number.
88
Highest 2-digit number = 99Highest 1-digit number = 999 - 9 = 90 two-digit numbers90.
100. The highest 3 digit number divisible by 9 is 999 (111 times). The highest 2 digit number divisible by 9 is 99 (11 times). The difference is 100.
99 is odd and if you added one more it would be 3 digit.
The highest digit is one less than the base used for counting. So in binary (base 2), the highest digit is 1 In octal (base 8), the highest digit is 7 In decimal (base 10), the highest digit is 9 In hexadecimal (base 16), the highest "digit" is 15. The symbols A, B, C, D, E and F represent the "digits" 10, 11, 12, 13, 14 and 15. And so on.
The largest seven-digit number in base 2 is 1111111. In decimal, this binary number equals 127, as it represents (2^6 + 2^5 + 2^4 + 2^3 + 2^2 + 2^1 + 2^0). Each digit in this number is a '1', indicating that all positions are filled with the highest possible value in binary.