Using the same tiles to pave the floor, it costs 320 yuan to pave 64 square meters. In this way, how many tiles are needed to pave 20 square meters.
用同样的瓷砖铺地，铺64平方米要320块，照这样，铺20平方米要多少块．
<gadget id="calculator">64 / 320</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">20 / (1/5)</gadget>
<output>100</output>

<result>100</result>