How to calculate percentages in LESS CSS?

Question

I would like to calculate the width of child-container (div etc) in percentages depending on the parent container with LESS CSS.

I am using the forumula by Ethan Mar

Answer 1

According to the LESS CSS website, you need to change the order of your equation

The output is pretty much what you expect—LESS understands the difference between colors and units. If a unit is used in an operation, like in:

@var: 1px + 5;

LESS will use that unit for the final output—6px in this case.

It should be:

width: 100%*(140/620);

Answer 2

Maybe the percentage function didn't exist when OP was asking but for future reference I add this answer.

div.child-container {
    width: percentage(140/620);
}