The product of 4.9 minus 2.9 and 0.5 is 1.65 less than 5 times of a number. Find a certain number.
4.9减去2.9与0.5的积比一个数的5倍少1.65，求某数．
<gadget id="calculator">4.9 - 2.9</gadget>
<output>2</output>

<gadget id="calculator">2 * 0.5</gadget>
<output>1</output>

<gadget id="calculator">1 + 1.65</gadget>
<output>2.65</output>

<gadget id="calculator">2.65 / 5</gadget>
<output>0.53</output>

<result>0.53</result>