Define an array of numbers in JavaScript: $55\mathrm{.}6,10\mathrm{.}2,$ and $7\mathrm{.}3.$ You have to write two functions. The first function will add $0\mathrm{.}5(+0\mathrm{.}5)$ to each number in the array, while the second will subtract $0\mathrm{.}2(-1\mathrm{.}2)$ of each number in the array. Before doing any operation, you have to check if the number is less than $0\mathrm{.}5.$ If it is$,$ do not subtract $1\mathrm{.}2.$

Suppose the span tag used to display the number in HTML code is like this:

Please note that you cannot use jQuery or any external library.

It is important to explain each line of code in detail.