mml=<math xmlns="http://www.w3.org/1998/Math/MathML"><mfenced open="|" close="|" separators="|"><mrow><mo>?</mo><mo>-</mo><mn>45</mn></mrow></mfenced><mo>=</mo><mn>40</mn><mo>&#xB1;</mo><mfenced separators="|"><mrow><mo>?</mo><mo>-</mo><mn>45</mn></mrow></mfenced><mo>=</mo><mn>40</mn></math>