Xiao Ming has 16 shells, and Xiao Hong has 12 shells. How many shells did Xiao Ming give Xiao Hong, and they both had the same number of shells.
小明有16个贝壳，小红有12个贝壳．小明给小红多少个贝壳，两人贝壳个数同样多．
<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<gadget id="calculator">4 / 2</gadget>
<output>2</output>

<result>2</result>