In order to implement audio-visual teaching, Hope Primary School bought back 72 TV sets and VCD machines. The ratio of TV sets to VCD machines was 5:4. After buying back some VCD machines, the ratio of TV sets to VCD machines was 8:7. , How many VCD players did you buy back?
希望小学为了实施电教化教学，共买回电视机与VCD机72台，电视机与VCD机台数比是5：4，又买回一些VCD机后，电视机与VCD机地比是8：7，又买回VCD机多少台？
<gadget id="calculator">5 + 4</gadget>
<output>9</output>

<gadget id="calculator">72 / 9</gadget>
<output>8</output>

<gadget id="calculator">7 / 8</gadget>
<output>7/8 = around 0.875</output>

<gadget id="calculator">5 * 8 * (7/8)</gadget>
<output>35</output>

<gadget id="calculator">4 * 8</gadget>
<output>32</output>

<gadget id="calculator">35 - 32</gadget>
<output>3</output>

<result>3</result>