Divide 105 dictionaries to the fourth and fifth grades according to the ratio of 3:4, how many copies will the fourth grade get.
把105本字典按3：4分给四、五两个年级，四年级分得多少本．
<gadget id="calculator">3 + 4</gadget>
<output>7</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">105 * (3/7)</gadget>
<output>45</output>

<result>45</result>