Answer:
2B
3D
Step-by-step explanation:
2A is
a/b + -a/-b = a/b + a/b = 2a/b
this is NOT 0/0. you can't add numerator and denominator. when you have the same denominator, you can only add the numerator.
and don't forget : -×- and -/- are both + !
2B
you do not multiply anything. you ADD (but again NOT the denominators) !
and +×- or +/- = - !
overall this this adding a negative number to the same positive number. the result : always 0
2C
cannot be added like that. first you would have to bring both to a common denominator. but then you ADD !
2D
very similar to 2C.
3
5 + 7 = 12
5 - 6 = -2
these are the 2 integers 7 units away from 5.
