There are 30 cards, write 1, 2, 3...30 respectively. Choose 2 pieces each time to form a division formula. Among all the division formulas formed, how many division formulas are there in which the quotient is an integer and there is no remainder?
有30张卡片，分别写上1，2，3…30．每次选2张组成一个除法算式，在组成的所有除法算式中，商是整数没有余数的除法算式一共有多少个．
<gadget id="calculator">29 / 1</gadget>
<output>29</output>

<gadget id="calculator">28 / 2 / 1</gadget>
<output>14</output>

<gadget id="calculator">30 / 1 / 2 / 1</gadget>
<output>15</output>

<gadget id="calculator">30 / 1 / 15</gadget>
<output>2</output>

<gadget id="calculator">2 * 3</gadget>
<output>6</output>

<gadget id="calculator">1 * 5</gadget>
<output>5</output>

<gadget id="calculator">29 + 14 + 9 + 6 + 5 + 4 + 3 + 6 + 5</gadget>
<output>81</output>

<result>81</result>