The small shopping department is going to make a glass counter with a length of 2.5m, a width of 45cm and a height of 97cm. Now it needs to install angle irons on all sides of the counter. How many meters of angle irons are needed at least?
小买部要做一个长2.5m、宽45cm、高97cm的玻璃柜台，现在要在柜台各边都安上角铁，至少需要多少米的角铁？
<gadget id="calculator">45 / 100</gadget>
<output>9/20 = around 0.45</output>

<gadget id="calculator">97 / 100</gadget>
<output>97/100 = around 0.97</output>

<gadget id="calculator">2.5 + (9/20) + (97/100)</gadget>
<output>3.92</output>

<gadget id="calculator">3.92 * 4</gadget>
<output>15.68</output>

<result>15.68</result>