17
12 in all, of which four contain repeat values.
1-4-9, 1-5-8, 1-6-7, 2-3-9, 2-4-8, 2-5-7, 2-6-6, 3-3-8, 3-4-7, 3-5-6, 4-4-6, 4-5-5
14
27
There are 165 of them and I do not have the patience to list them all.
51 Numbers30-9 is equal to the number of two digit numbers21*2=42Then you add the 9 single digit ones42+9=51
28
14
27
9+8+2=19 9+7+3=19 9+6+4=19 There are a limited number of possibilities but there are absolutely loads
There are 165 of them and I do not have the patience to list them all.
51 Numbers30-9 is equal to the number of two digit numbers21*2=42Then you add the 9 single digit ones42+9=51
positive combinations:14 positive combinations not counting the same one just flipped:7 combinations including negatives: infinate
20
28
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.
10
Five of them.
An infinite number of combinations of fractions can be aded together to equal three fourths.