In a classroom teacher has 20 boxes, they issues 8 boxes gifted to their students. Then how many boxes they had?
Choose one
A) 9
B) 28
C) 12
D) 15
E) 9
20-8= 
<gadget id="calculator">20-8</gadget>
<output>12</output>
12. Answer is 12
<result>C</result>
In a classroom teacher has 20 boxes, they issues 8 boxes gifted to their students. Then how many boxes they had?