<p>IF&nbsp; U<span class="math-editor mathquill-rendered-math"><span class="binary-operator">=</span><span class="non-leaf"><span class="scaled paren" style="transform: scale(1, 1.05);">{</span>1,2,3,4,5,6<span class="scaled paren" style="transform: scale(1, 1.05);">}A</span></span><span class="binary-operator">=</span><span class="non-leaf"><span class="scaled paren" style="transform: scale(1, 1.05);">{1,2,3</span><span class="scaled paren" style="transform: scale(1, 1.05);">} <span style="font-family: Times New Roman, Symbola, serif;"><em>and B={3,4,5,6} then find</em></span></span></span>&nbsp;<span class="math-editor mathquill-rendered-math"><span class="roman font"><var>A</var></span><sup class="non-leaf">&prime;</sup><var>a</var><var>n</var><var>d&nbsp; </var><span class="roman font"><var>B</var></span><sup class="non-leaf">&prime;</sup></span> ?</span></p>