Abby paid $65 for a computer back-up system
and $17 for a cable. She
paid $100 in cash. How
much change should she
get back?

$18

Step-by-step explanation:

$65 + $17 is 82 so then she paid $100 so then I would subtract $100 and $82 which is $18 so she will receive $18 back. Hope this helps.  

$18

Step-by-step explanation:

65 + 17 = 82

100 - 82 = 18

Doubls check:

82 + 18= 100

Final

She would get $18 back for change.