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 track of the score as Cole Palmer cut their defence apart and destroyed their goal difference.
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, this season. He has scored 11 goals in his last five home games.
It is tempting to wonder where they would be without him.
For Chelsea, victory made it five out of five on Monday nights this season, but they could not complete victory without a hint of embarrassment, as players bickered over who should take the penalty.
Noni Madueke wanted to take it because he thought he had won it, although it later transpired it had been awarded for an earlier foul on Palmer. Nicolas Jackson, who had scored the fourth of the night just before half time, wanted to take it, too.
Then Palmer stepped forward and took the ball, supported by captain Conor Gallagher.
The home crowd booed as Jackson refused to retreat quietly. Even after Palmer had beaten Jordan Pickford from the spot with his trademark nonchalance, Jackson had to be reminded by Madueke to go and congratulate the scorer. Something he did very reluctantly.
Otherwise, it was a wonderful night for Mauricio Pochettino, capped by a popular sixth, the first of his senior career for Alfie Gilchrist. That went down well with the home crowd as Chelsea closed in on the European places, with a little momentum building.
They may also have stumbled into their best attacking balance, although few opponents will be as accommodating as Everton, for whom injury was added to insult when Jarrad Branthwaite and Nathan Patterson both went off injured in the second half.
Relegation concerns deepen ahead of Sunday’s clash with relegation rivals Nottingham Forest, and this hammering means those teams step out at Goodison Park on the same goal difference. Sean Dyche has six days to patch up their confidence as well as battered bodies.