Passing maths test the key to title

It seems a bit like wringing a dirty mop out on the fire that's just warmed the entire house but after the glow of Cardiff it all comes down to the maths. The Calcutta Cup match swung along lustily but it too added not so much to the romance of a hard game well fought, but to the sums. The scoreboard has always demanded the ability to count. Now we must subtract.