Simple calculation: 99-1+98-2+97-3+96-4.
简便计算：99-1+98-2+97-3+96-4．
<gadget id="calculator">99 - 1</gadget>
<output>98</output>

<gadget id="calculator">98 - 2</gadget>
<output>96</output>

<gadget id="calculator">97 - 3</gadget>
<output>94</output>

<gadget id="calculator">96 - 4</gadget>
<output>92</output>

<gadget id="calculator">98 + 96 + 94 + 92</gadget>
<output>380</output>

<result>380</result>