10/18 100%(одно из решений)

.formula .column {
display: table-column;
background-color: #ffbaba;

}

.formula .column-group {
display: table-column-group;

}

.formula .column-group .column {
background-color: #b2fdd0;

}

.formula .content-important {
background-color: #fffebc;

}

.formula {
display: table;
margin: 10px;
width: 500px;
border-collapse: collapse;

}

.formula ul {
display: table-row;

}

.formula li {
display: table-cell;
border: 1px solid #777777;
text-align: center;
vertical-align: middle;
padding: 5px;

}

.formula .content {
display: table-row-group;

}

.formula header {
display: table-header-group;
background-color: #ffffff;

}

.formula p {
display: table-caption;
caption-side: bottom;
text-align: center;
margin: 0px;
padding: 10px;
font-size: 20px;

}