разделение в CSS

/* 
	Considering: 1rem = 10px
	.7rem = 0.7rem

	Note: Turns more easy calculating 1rem beeing 10px that the 
	font normal size that is 16px.
*/

Incorrect:
calc(100% - 3 * .7rem) / 4;

Correct:
calc((100% - 3 * .7rem) / 4);
Wide-eyed Wolf