The science and technology group of the school exhibited students' scientific and technological works. There are 120 scientific and technological works for the lower and middle grades, and 168 scientific and technological works for the middle and upper grades. It is also known that the works of the lower grades are works of the upper grades (3/7). How many pieces of senior work are on display?
学校科技组展出学生的科技作品，低、中年级的科技作品共有120件，中、高年级的科技作品共有168件，又知道低年级的作品是高年级作品的(3/7)．展出的高年级作品有多少件？
<gadget id="calculator">168 - 120</gadget>
<output>48</output>

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

<gadget id="calculator">1 - (3/7)</gadget>
<output>4/7 = around 0.571429</output>

<gadget id="calculator">48 / (4/7)</gadget>
<output>84</output>

<result>84</result>