There is no simple formula for that; I suggest you look up the prime numbers in a table of prime numbers, analyzing each prime number in the range 10-99 whether it fulfills this specific criterion.
84.42 or 42.21
It is the unit's digit of the product of the unit's digits. For example, the units digit of 123456 * 4689 is simply the units digit of 6*9 = 54, which is 4.
What is the units digit of the least whole number greater than 1000 whose digits are all different?
The units digit of a two digit number exceeds twice the tens digit by 1. Find the number if the sum of its digits is 10.
Look at the tens digit. If it is 5 or more, add 100 to 9876. Then replace all the digits to the right of the hundreds digit (the tens and units digits) by zeros. The answer is therefore 9900
42.21 or 84.42
84.42 or 42.21
It is the unit's digit of the product of the unit's digits. For example, the units digit of 123456 * 4689 is simply the units digit of 6*9 = 54, which is 4.
The units digit of 159*445*7762*39 is the units digit of the product of the units digits of the four numbers, that is, the units digit of 9*5*2*9 Since there is a 5 and a 2 in that, the units digit is 0.
Any two digit number in which: (a) the units digit is not 0, and (b) the two digits are different will form a new 2-digit number when the digits are interchanged.
What is the units digit of the least whole number greater than 1000 whose digits are all different?
The units digit of a two digit number exceeds twice the tens digit by 1. Find the number if the sum of its digits is 10.
-4
The last two digits (the tens and units) are divisible by 4.This is equivalent to the following two conditions:If the tens digit is even, the units digit must be 0, 4 or 8If the tens digit is odd, the units digit must be 2 or 6For divisibility by 9, calculate the digital root: this is the sum of all the digits in the number. Repeat with the digits of this number - and keep repeating until you are down to a single digit. It that is 9, then the number is divisible by 9 and if not, it is not.
I am a three digit number. all of my digit is multiples of 2. my hundreds digit is the lowest even number. the sum of my digits is 16. the units digit is the same as the difference between my hundreds and tens digits.
The prime numbers with a units digit of 1 in the range 1 - 121 are :- 11, 31, 41, 61, 71 and 101.......making 6 primes in total.
To find the units digit of (27^{27}), we can look at the units digit of (27), which is (7). We then need to find the units digit of (7^{27}). The units digits of the powers of (7) cycle every four terms: (7^1 = 7), (7^2 = 49) (units digit (9)), (7^3 = 343) (units digit (3)), and (7^4 = 2401) (units digit (1)). Since (27 \mod 4 = 3), the units digit of (7^{27}) is the same as that of (7^3), which is (3). Thus, the units digit of (27^{27}) is (3).