.vec {
	line-height: 25px;
	background-image: url(fleche.svg);
	background-repeat: no-repeat;
	background-position: top right;
	padding-top: 5px;
}
.alg {
	line-height: 25px;
	background-image: url(fleche.svg);
	background-repeat: no-repeat;
	background-position: top left;
	padding-top: 5px;
}
.frac {
	display: inline-block;
	text-align: center;
	vertical-align: middle;
}
.num {
	display: block;
	padding-bottom: 4px;
	border-bottom: 1px solid;
}
.den {
	display: block;
	padding-top: 5px;
}