In the first set of brackets 3.14 appears as numerator and denominator, so they cancel out leaving 180/16, which divides down to 45/4 because 4 goes into top and bottom. So the answer should be 11.25. Why did your teacher get 21.25? Have you asked? The fraction 180/3.14 looks suspiciously like the conversion factor from radians to degrees (180/(pi)). Could it be that this was an attempt to convert 3.14/16 from an angle in radians to an angle in degrees that went wrong? Perhaps your teacher had a fixation on 85 instead of 45? Perhaps the bell had just gone to mark the end of the lesson and your teacher had another class to go to?