Are there any other details as to what the numbers are? otherwise there are six possibilities for this
12+54=66
66=6(_+_)
11=(_+_)
1) 0, 11
2) 1, 10
3) 2, 9
4) 3, 8
5) 4, 7
6) 5, 6
Answer:

Step By Step Explanation:
Apply Rule - (-a) = a

Multiply: 4 · 6 = 24

Expand 
= 
Simplify 
= 
━ Mordancy ━
12 : 19...................