There are 15 tables in the school's cafeteria. Each table can seat 10 people. Usually, only 1/10 of the seats are left unseated. How many seats are usually taken?
The cafeteria can seat 15 x 10 = 
<gadget id="calculator">15*10</gadget>
<output>150</output>
150 people.
Usually, 150 x 1/10 = 
<gadget id="calculator">150*1/10</gadget>
<output>15</output>
15 seat are unseated.
Thus, 150 - 15 = 
<gadget id="calculator">150-15</gadget>
<output>135</output>
135 seats are usually taken.

<result>135</result>