56.
Tens digit is greater than 4 and less than 6 so it can only be 5,
so the number is 5X.
It is one less than the number whose digits sum to 12, so its digits sum to 12-1 = 11
→ 5 + X = 11 → X = 11 - 5 = 6
→ the number is 56.
97 is one example.
The largest 3 digit number whose digits are all primes is 777. The largest 3 digit number with different prime digits is 753.
The largest three digit prime number whose digits are all primes is 773.
1
The 2-digit number must be 20, because it is the only 2-digit number whose sum of its two even digits, 2 + 0 = 2, is greater than the product of its two even digits, 2 x 0 = 0. Moreover, 20 is a product of the two consecutive integers 4 and 5.
What is the units digit of the least whole number greater than 1000 whose digits are all different?
97 is one example.
The largest 3 digit number whose digits are all primes is 777. The largest 3 digit number with different prime digits is 753.
Find a four digit number whose digits will be reversed when multiplied by nine?
The largest three digit prime number whose digits are all primes is 773.
Nine hundred thirty (930) is the highest three digit number whose digits have a sum of 12. 9+3+0=12. Any numbers higher than that will give you an sum greater than 12.
1
The 2-digit number must be 20, because it is the only 2-digit number whose sum of its two even digits, 2 + 0 = 2, is greater than the product of its two even digits, 2 x 0 = 0. Moreover, 20 is a product of the two consecutive integers 4 and 5.
279,999,720
992
7777
111111