Check out example codes for "nth-child(2n+1)". It will help you in understanding the concepts better.

Code Example 1

p:nth-child(2)
 {

     
 background: red;

 }

Code Example 2

/* Select the first list item */
li:nth-child(1) { }

/* Select the 5th list item */
li:nth-child(5) { }

/* Select every other list item starting with first */
li:nth-child(odd) { }

/* Select every 3rd list item starting with first */
li:nth-child(3n) { }

/* Select every 3rd list item starting with 2nd */
li:nth-child(3n - 1) { }

/* Select every 3rd child item, as long as it has class "el" */
.el:nth-child(3) { }

Code Example 3

li:nth-child(-n+5) {
    color: green;   
}

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