Every April 23rd is "World Book Day". All the books in Knowledge Book City will be discounted by 10%. How much did you actually spend?
每年4月23日是"世界读书日"，知识书城所有图书九折优惠，小涵买了一本原价35元的《海底探秘》和一本原价45元的《世界神秘之旅》，小涵实际用了多少钱？
<gadget id="calculator">35 + 45</gadget>
<output>80</output>

<gadget id="calculator">90 / 100</gadget>
<output>9/10 = around 0.9</output>

<gadget id="calculator">80 * (9/10)</gadget>
<output>72</output>

<result>72</result>