1a) The distance is always positive. You can write the expression for the distance any of several ways: adding distance from zero (when the directions are opposite); subtracting the smaller number from the larger; taking the absoute value of the difference; reflecting both negative numbers to the positive side of the number line before subtracting the smaller from the larger; (and maybe other methods, as well).
- 12+19 = 31 . . . . adding distances from 0
- 7 -2 = 5 . . . . . . making both numbers positive, then subtracting the smaller
- 25+1 = 26 . . . . adding distances from 0
1b) Most uses of the wording "difference of ___ and ____" intend that the second number be subtracted from the first. There are exceptions, but this isn't likely to be one of them.
- -12 -19 = -31
- -2 -(-7) = -2+7 = 5
- 25 -(-1) = 25+1 = 26