(2.5+3.6)*2(1/4)+3.9*2(1/4).
(2.5+3.6)*2(1/4)+3.9*2(1/4)．
<gadget id="calculator">6.1 * 2.5</gadget>
<output>15.25</output>

<gadget id="calculator">3.9 * 2.5</gadget>
<output>9.75</output>

<gadget id="calculator">15.25 + 9.75</gadget>
<output>25</output>

<result>25</result>