Find the common factors of the pair of numbers. Begin with the smallest. <br> 16 and 28: <input min="0" type="number" id ="imp4pg006q7a_1" class="lineinput" placeholder="?" /> <input min="0" type="number" id ="imp4pg006q7a_2" class="lineinput" placeholder="?" /> <input min="0" type="number" id ="imp4pg006q7a_3" class="lineinput" placeholder="?" />