Indicate which property is illustrated in step 4.

step 1
(-8) + 8 + 2(8 + 2)
=
(-8) + 8 + (2 • 8) + (2 • 2)

step 2

=
(-8) + 8 + (16) + (4)
step 3

=
(-8) + 8 + 20
step 4

=
0 + 20
step 5

=
20