There are 45 students in class 61. Now there are two kinds of newspapers to subscribe to, and each person must subscribe to at least one kind of newspaper. Now (4/5) of the students have subscribed to "Times English News", and (2/3) of the students have subscribed to "Journal of Primary School Mathematics", how many people subscribe to both newspapers?
六1班有45名同学，现在有两种报纸要订阅，每人至少订阅一种报纸，现在有(4/5)的同学订了《时代英语报》，(2/3)的同学订阅了《小学数学报》，两种报纸都订阅的有多少人？
<gadget id="calculator">4 / 5</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">(2/3) - 1</gadget>
<output>-1/3 = around -0.333333</output>

<gadget id="calculator">(4/5) + (-1/3)</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">45 * (7/15)</gadget>
<output>21</output>

<result>21</result>