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.
The biggest two-digit number is 99. It is the highest value that can be represented with two digits, where both digits are at their maximum (9).
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.