She finds him sitting at his desk staring at an empty page, pen poised. “Do you know that forty-eight is 110000 in binary, 60 in octal, 40 in duodecimal and 30 in hexadecimal?”

He keeps his eyes fixed on the empty page. “No. Well, I would if I worked it out but I have other things on my mind just now.”

“Do you know that forth-eight in Roman numerals is XLVIII?”

“Yes.” His eyes still haven’t moved.

“Do you know that forth-eight in Hebrew numbering is מ”ח, which is also the root of the word that means protest?”

He turns his head towards her, blackness creeping over his face. “Yes. Now if you don’t mind…”

“Do you know that the factorisation of forth-eight is 2 x 2 x 2 x 2 x 3?”

“Yes, but…”

“Do you know that forty-eight is half of ninety-six?”

“Yes.” Anger is creeping into his voice.

“Do you know that forty-eight is a third of a gross and four dozen?”

“Yes.” The anger is more noticeable.

“Do you know that forty-eight is a highly composite number, a semiperfect number, the second 17-gonal number, the smallest number with exactly 10 divisors, a Stormer number and a Harshad number?”

“Yes. Well – no. I don’t even know what those things mean, but really I’m trying…”

“Do you know that forty-eight is the atomic number of cadmium?”

“No. Look, please…”

“Do you know that Siddhartha Gautama sat under a bodhi tree for forty-eight days attempting to understand the nature of reality and the universe, and ended up with Buddhism?”

He scowls at her. “No, I don’t. And I don’t give…”

“Do you know that Johann Sebastian Bach’s Well-Tempered Clavier is informally known as The Forty-Eight because it consists of a prelude and a fugue in each major and minor key, for a total of forty-eight pieces?”

He throws down his pen with an action that causes its components to separate. “Yes, I had heard of that, but why…”

“Do you know that forty-eight is the code for international direct dial phone calls to Poland?”

He breathes out slowly to calm himself. It doesn’t work. “No.” Ink is seeping onto the empty page.

“Do you know that ’48 is an alternate history novel by James Herbert?”

Surprisingly, he discovers his anger is seeping away. He is becoming resigned to this interruption. “How do you know all this?”

“Most of it’s in Wikipedia.”

“And why this fascination with the number forty-eight?”

Sally Quilford is forty-eight today.”

He’s smiling. “Why didn’t you tell me?”

“Err… I am telling you?”