8*15/(1/5)/4-21*0.25.
8*15/(1/5)/4-21*0.25．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">15 / (1/5) / 4</gadget>
<output>75/4 = around 18.75</output>

<gadget id="calculator">8 * (75/4)</gadget>
<output>150</output>

<gadget id="calculator">21 * 0.25</gadget>
<output>5.25</output>

<gadget id="calculator">150 - 5.25</gadget>
<output>144.75</output>

<result>144.75</result>