<p>Add</p>
<div>&nbsp; &nbsp;<span class="math-editor mathquill-rendered-math"><span class="non-leaf"><span class="scaled paren" style="transform: scale(1, 1.05);">(</span><span class="non-leaf"><var>a</var></span><span class="scaled paren" style="transform: scale(1, 1.05);">)</span></span><span class="binary-operator">+</span><span class="mtable non-leaf"><span class="mtr non-leaf"><span class="mtd"><span class="roman font">6</span></span><span class="mtd"><span class="roman font">4</span></span><span class="mtd"><span class="roman font">3</span></span><span class="mtd"><span class="roman font">2</span></span><span class="mtd"><span class="roman font">1</span></span></span><span class="mtr non-leaf"><span class="mtd">2</span><span class="mtd"><span class="roman font">4</span></span><span class="mtd"><span class="roman font">5</span></span><span class="mtd"><span class="roman font">2</span></span><span class="mtd"><span class="roman font">4</span></span></span></span><span class="non-leaf"><span class="scaled paren" style="transform: scale(1, 1.05);">(</span><span class="non-leaf"><var>b</var></span><span class="scaled paren" style="transform: scale(1, 1.05);">)</span></span><span class="binary-operator">+</span><span class="mtable non-leaf"><span class="mtr non-leaf"><span class="mtd"><span class="roman font">2</span></span><span class="mtd"><span class="roman font">4</span></span><span class="mtd"><span class="roman font">4</span></span><span class="mtd"><span class="roman font">6</span></span><span class="mtd"><span class="roman font">8</span></span></span><span class="mtr non-leaf"><span class="mtd"><span class="roman font">4</span></span><span class="mtd"><span class="roman font">3</span></span><span class="mtd"><span class="roman font">5</span></span><span class="mtd"><span class="roman font">4</span></span><span class="mtd"><span class="roman font">2</span></span></span></span></span></div>
<div><span class="math-editor mathquill-rendered-math"><span class="mtable non-leaf"><span class="mtr non-leaf"><span class="mtd"><span class="roman font">----------------------------------&nbsp; --------------------------------</span></span></span></span></span></div>
<div><span class="math-editor mathquill-rendered-math"><span class="non-leaf"><span class="scaled paren" style="transform: scale(1, 1.05);">&nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp; &nbsp;&nbsp;</span></span></span></div>