What is the sum obtained by multiplying the sum of 6.5 and 2.6 by 8.9 and adding 3.21?
6.5与2.6的和乘以8.9，再加上3.21，得到的和是多少．
<gadget id="calculator">6.5 + 2.6</gadget>
<output>9.1</output>

<gadget id="calculator">9.1 * 8.9</gadget>
<output>80.99</output>

<gadget id="calculator">80.99 + 3.21</gadget>
<output>84.2</output>

<result>84.2</result>