There are only two coins with face value of one yuan and five cents in the piggy bank of Nao Nao. When he checked, he found that the total value of these two coins was 90 yuan, and the number of one yuan coins was four times that of five cents. How many coins are there in this piggy bank?
闹闹的储蓄罐中只有面值是一元的和五角的两种硬币，他在清点时发现：这两种硬币共值90元，而且1元硬币的枚数是5角的4倍．这只储蓄罐中共有多少枚硬币？
<gadget id="calculator">0.5 + 4</gadget>
<output>4.5</output>

<gadget id="calculator">90 / 4.5</gadget>
<output>20</output>

<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">20 + 80</gadget>
<output>100</output>

<result>100</result>