For the first box on the left hand side, the answer is m < 1 + m < 2 = 180 as they are a linear pair
The first box in the right-hand column is "linear pair postulate" as its very similar to the previous line
The second box on the left-hand side is m < 1 + m < 2 = m < 2 + m < 3. Essentially we're doing replacements. Similar to how x+3 = 10 turns into 7+3 = 10 when we plug in x = 7
The second box on the right-hand side is "subtraction property of equality". We subtract "m < 2" from both sides to end up with m < 1 = m < 3
