Exchange coins for each other. There are 100 coins in Tiger's savings box. If you exchange all the two-cent coins into five-cent coins, the total number of coins becomes 73, and then you exchange all the one-cent coins into five-cent coins, and the total number of coins becomes 33. How many nickels were originally in the piggy bank?
把硬币互相兑换．小虎的储蓄盒里有100枚硬币，把二分硬币全部兑换成五分硬币，硬币总数变为73枚，再把一分硬币全部兑换成五分硬币，硬币总数变为33枚．储蓄盒里原来有五分硬币多少枚？
<gadget id="calculator">100 - 73</gadget>
<output>27</output>

<gadget id="calculator">2.5 - 1</gadget>
<output>1.5</output>

<gadget id="calculator">27 / 1.5</gadget>
<output>18</output>

<gadget id="calculator">18 * 2.5</gadget>
<output>45</output>

<gadget id="calculator">73 - 33</gadget>
<output>40</output>

<gadget id="calculator">5 - 1</gadget>
<output>4</output>

<gadget id="calculator">40 / 4</gadget>
<output>10</output>

<gadget id="calculator">10 * 5</gadget>
<output>50</output>

<gadget id="calculator">100 - 45 - 50</gadget>
<output>5</output>

<result>5</result>