m+4-m-12,6+n+8,6

To simplify the expression m+4-m-12, we can combine like terms:

m + 4 - m - 12 = (m - m) + 4 - 12 = 0 + 4 - 12 = 4 - 12 = -8

Therefore, m+4-m-12 simplifies to -8.

To simplify 6+n+8.6, we can combine like terms:

6 + n + 8.6 = 6 + 8.6 + n = 14.6 + n

Therefore, the expression 6+n+8.6 simplifies to 14.6 + n.