150 lighted lamps, each controlled by a pull switch, are numbered 1, 2, 3, ..., 150 in sequence. Pull the pull wires of the lamps numbered multiples of 3 once; then pull the pull wires of lamps numbered multiples of 5 once, how many lights are on after pulling.
150盏亮着的电灯，各有一个拉线开关控制，按顺序编号为1，2，3，…，150．将编号为，3的倍数的灯的拉线各拉一下；再将编号为5的倍数的灯的拉线各拉一下，拉完后亮着的灯数为多少盏．
<gadget id="calculator">150 / 3</gadget>
<output>50</output>

<gadget id="calculator">150 / 5</gadget>
<output>30</output>

<gadget id="calculator">150 - 50 - 30</gadget>
<output>70</output>

<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<gadget id="calculator">150 / 15</gadget>
<output>10</output>

<gadget id="calculator">70 + 10</gadget>
<output>80</output>

<result>80</result>