None. The sum of one digit can't be twice the size of the digit.
Only one . . . . . 18
The sum is the total of numbers added together.
It is not clear what the question means: there are 31 2-digit numbers that can be expressed as a sum of two squares.
-3
None. The sum of one digit can't be twice the size of the digit.
There are four of each.
Only one . . . 999 .
what is the least possible sum of two 4-digit numbers?what is the least possible sum of two 4-digit numbers?
2,4,6,8,10,12,14,16,18
1
There are 5460 five digit numbers with a digit sum of 22.
There are five such numbers.
111 and 201
Only one . . . . . 18
The sum is the total of numbers added together.
9