Severus made a mental note to come back for the Arithmancy book, mainly because he did not relish buying it in Lucius' presence.
"Well enough," he said his voice a bit acerbic as he ducked away a bit from Lucius' hand. "Thought I'd try this growing thing I'd heard so much about. Who knows, might even end up taller than you." He almost made a quip about being a real live boy but knew that the reference would be both unfamiliar and dangerous, being Muggle.
"You've been well then? Keeping busy?" He'd heard some rumours about what might be keeping Lucius Malfoy busy, but of course one did not just ask such things. Still, his interest was piqued, most definitely.