I don't get this, is it 180° because of the straight line? And if it is what would the angles be for the rest?

Don't listen to that other guy. He's just guessing.
Answer:
M<1=112
Reasoning: The straight line represents a 180° Angle, and subtracting the excess 68° from the other angle results in a total of 112° for the opposite angle
Answer:
M<5=90°
Reasoning: The square on the corner of the angle indicates that it is, in fact, a right angle. All right angles are 90°.
Now there is a reason I put 5 before the others
Answer:
M<3=68°
Reasoning: It is opposite of the other 68° Angle, and if you notice, it lines up perfectly with the intersecting lines.
Answer:
M<4=22
Reasoning: By taking the 180° Angle, and subtracting the 90° Right angle and the 68° Angle, the resulting number is 22.
I hope this helped!
Thanks!
Your friend in Answering,
~Steve