Well, simply young soul, you have to add up everything you have so far and subtract that by 100% because we know 100%= 100/100 just like 65%= 65/100, 18%= 18/100 and 10%= 10/100.
65
18 If all that added together is 93 we can put this over 100 just like
+10 all the other ones. 93/100= 93%
--------- Now take the whole number (100) and subtract
93 100-93= 7 which is 7%
7% of the human body is made up of other elements. Hopes this
helps!! :D
