There are 0, 1, 2, 3, 4, 5, 6, seven cards with different numbers, two cards are taken each time to form a two-digit number. So how many different two-digit numbers can these number cards form?
有0，1，2，3，4，5，6，七张不同数字的卡片，每次取两张卡片，组成一个两位数．那么这些数字卡片可以组成多少个不同的两位数？
<gadget id="calculator">6 * 6</gadget>
<output>36</output>

<result>36</result>