I’ve never been good at math.

I’ve think of my brain as a bustling Victorian house, well-lit and full-porticoed, full of family and servants working away at word jobs, fixing grammar, cobbling paragraphs, combining ideas, happy, competent, at home there.

And then some mathematical task, even a basic question of arithmetic, arrives, plodding in on an old wheezing horse, and then some old mechanical gears clunk into action and the drawbridge over the crocodile-filled moat — because it goes from being a Victorian mansion to a Dark Age fortress — slams up.

No math for me!

But when I start thinking of the death of my daughter, my older daughter, my first-born child, Shira Palmer-Sherman, whom I loved so deeply, I seem to veer off improbably into numbers.

I’d veer off into anything to avoid talking about Shira’s death. Even numbers. But the problem is that nothing makes it go away.

So, the numbers.

Shira was 20 when she died, and we now are marking her 15th yarzheit. She’s been dead almost as long as she was alive – 75 percent as long. Her sister, Miriam, was 17 when Shira died, and she’s almost 32 now. Miriam, who now is a mother, already has spent almost as much time as an only child as she did as a little sister, and soon that balance will shift forever.

It’s the inexorable unstoppable arithmetic of death.

Oh, and the way I can go from jokes about arithmetic and elaborate metaphors about architecture to the bluntness of death – that’s the emotional lability that accompanies sudden death. You’re fine, walking in the so-green park, noticing the glint of the sun and the sharpness of the shadows and the improbable colors of the flowering trees and the shape of the hills, watching your dogs take huge pleasure at stopping at every single hydrant and fence and invisible pee marker — and all of a sudden you’re in a deep foul-smelling muddy black pit. Grief has sandbagged you once again. Under the path was a hole, and you’ve fallen into it. You cannot climb up its slimy walls. You can get no purchase on it.

And then somehow you surface, as suddenly as you fell. You’re back in the daylight. You keep walking. You remember that there might be another hole, so your next steps are tentative — and then you can’t keep walking at that pace, that funeral pace, so you speed up, and from the outside you look normal, and you keep going until you fall into the next hole. Whenever that might be.

So I can evade the main subject for a very long time. Dance around the wonder that was Shira and the… the… the – I am not someone often at a loss for words, but truly words fail when I try to describe the impossibility of her gone-ness. The deadness of the world without her, the flatness, the grayness. The wrongness of it.

Shira was a vest-pocket Venus, a short, narrow-boned but somehow voluptuous, huge-eyed person, with porcelain skin and gleaming dark hair and delicate freckles. She radiated life.

Yes, right, of course, anyone would think. She was your daughter. But she was a force, an experience, a person who lived so intensely, so intently, that life burst from her. It’s a cliché but also a truth that her 20 years contained more than 20 years of a more normal person’s experience.

More math!

This Shabbat, my husband and I had an aliyah to mark Shira’s upcoming yarzheit, which falls, as if it had been planned, on the first day of Chanukah. (The last time we saw her as herself, not as a brainless body on a bed, tethered by machines that were living for her, was on Thanksgiving. Her funeral was on Christmas Eve. The whole end of the year is one long reminder of grief for us.)

Our rabbis said wonderful things about Shira, whom they knew and loved, and then later, at kiddush, many people told us that they remembered her too. When she was in high school she led children’s services, and her imagination, creativity, warmth, and charisma imprinted themselves on the children – now college students! – and their parents. But she was so much more than that.

Shira’s name, of course, means song, and she was one. She was a performer; her voice was adequate but her spirit, her sense of joy, her wit, her passion, her insight, and her kindness made her a compulsively watchable performer and extraordinary friend. She was deeply rooted in the Jewish world but not confined to it. Her interests included children’s services and egalitarian Judaism; American and British literature and history; and people’s relationships and stories. She had an astonishingly encyclopedic memory for music, gleaned from it is not exactly clear where; although some people her age might be able to sing the tooth-breaking lines of one of her favorite Noel Coward songs, “Mad Dogs and Englishmen,” it is likely that few people of them could break into a spontaneous version of, say, his “Don’t Let’s Be Beastly to the Germans.” (It’s a song that Coward said he wrote during the war years as a satire against those very few Brits who were taking too tolerant a view of their enemies, and includes such lines as “Let’s be sweet to them/And day by day repeat to them/That sterilization simply isn’t done./Let’s sweetly sympathize again/And help the scum to rise again/But don’t let’s be beastly to the Hun.”

And then there was Cole Porter, another of her heroes. She would high-kicking in the living room, belting out the lyrics to “Can-Can.” “If a tomcat in Pekin can, if a dachshund in Berlin can, if a sardine in tin can, baby you can can can too!”

And baby could she can can!

It is hard to know that all that luminesce is gone. She will never marry her boyfriend, one of the swarm of boys who followed her like slack-jawed lemmings throughout her time at Harvard, and who showed us such kindness when she lingered comatose in the hospital and then when we sat shiva for her. She will never have children, write books, lead people, laugh, dance, cry, tell stories, tease, or breathe again.

All we have of her is memories.

Because she sang so much, though, because her song was so sweet, so piercing, so clever, so original, so funny, so undeniably and unmistakably only hers, it still echoes in our ears.

It’s all we have left, but at least we have that. May her memory always be as it is now – a blessing.