Calculate with a simple method: 7.74*(2.8-1.3)+1.5*2.26.
用简便方法计算：7.74*(2.8-1.3)+1.5*2.26．
<gadget id="calculator">2.8 - 1.3</gadget>
<output>1.5</output>

<gadget id="calculator">7.74 * 1.5</gadget>
<output>11.61</output>

<gadget id="calculator">1.5 * 2.26</gadget>
<output>3.39</output>

<gadget id="calculator">11.61 + 3.39</gadget>
<output>15</output>

<result>15</result>