Everton supporters are accustomed to keeping a calculator close.
In this season of deducted points and financial irregularities it comes in handy, and at Stamford Bridge it helped them keep up with the score as Cole Palmer left their defence in tatters and the goal difference took some heavy damage.
Rampant Palmer scored four, the first three before half an hour had elapsed and the fourth, to make it 5-0 from the penalty spot to reach 20 goals in the Premier League. He has scored 11 goals in his last five home games.