To make the list of two-digit numbers with digits that add up to 10, first write the pairs of single-digit integers that add up to 10. They are (1,9), (2,8), (3,7), (4,6), (5,5). Then recognize that each of these pairs of numbers, except 5, can be combined in two different ways to make two-digit numbers that satisfy the problem.
19 and 91
28 and 82
37 and 73
46 and 64
55
So there are nine two-digit numbers with digits that add up to 10.
Assuming you mean digits and not didgets, the answer is 6.
36
20 number
67
add numbers below to each number at the top
Assuming you mean digits and not didgets, the answer is 6.
36
There are a variety of three digits that add up to 25. Examples include 9, 8 and 8.
Multiples of 3 are easy to identify. Their digits add up to a multiple of 3.
20 number
17
67
None. The only way for it to be possible would be 3 zeros which is not considered a 3 digit numbers.
add numbers below to each number at the top
Two-digit prime numbers whose digits add up to 10 are:193773
72
39 and 48