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.
1
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.
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
111111
7777