I invent fish maths

This is a problem with home education. There's always a subject or an area you're bloody rubbish at talking about.

In Grit's case, it's maths. Now I can work out ten per cent off the price of a decent-sized handbag, simultaneously sustaining in my brain the knowledge that it's fifty per cent overpriced and that there is a finite limit to my bank account. Yet I will still come out with the answer that it's a bargain.

Some people say that is enough. This is real-life maths, suitable for a real-life world. And a child starts showing inclination and disposition in this real world soon enough. If they are going to be sharp with maths, it'll show, you'll know. They lead the way. You know how to help.

Similarly, if they are determined to become an illustrator, then there is little point forcing them through two hundred and seventy-two school hours of algebra hoops. You can make the kid jump if you poke enough pointed sticks behind them, but the numbers won't travel along.

These examples really support an education that is responsive, child-centred, easy going. One which doesn't set up kids for failures but which matches their inclinations and needs.

Of course you have to know each child. And if you are determined to introduce higher level maths even with your illustrator, you could. Theoretically, I could do the algebra in a way relevant to illustrative techniques and printing requirements. Then it will stick in their brain like cement mortar to brick. I could do that, if I knew any algebra.

But this is my point. There is always that area for which your child needs your help, but which you are crap at. They may have started to help themselves, looked at it, burst into tears, and looked to you for explanation.

For example. Shark says she would like to study marine biology. I have put her in front of a lot of fish over many years. Recently, she has become aware of a need for maths to sit a degree course. I guess there is a little maths to be done there, what with the waves and all. You see I'm already at my limits.

And this is where I feel my great weakness. I am simply crap at maths. I start off with good intentions, which is bad enough. But then it all gets worse. This is how it goes.

'Well, Shark. I'm sure I can help you understand decimals. Um. Here is the number ten. You can divide it up! Into bits and then bits of bits, like points. Um. Um. OK, let's think of this number as a big fish. And we are dividing it up into bits and points. Um. OK, here is a fin. It's a green fin, and the fish has ten green fins all over. I'm chopping off one of the fins. Yes, maybe I'm a predator, and I eat green fins from this fish. Now I'm pulling off some more fins. There. I've collected all these fins. And that makes point six. I think. Anyway. Let's say it does. Get it? Oh. Go and ask daddy.'

A simple answer would be convenient, but I know life doesn't work like that. So I shall continue to stick her in front of more maths websites, keep drawing pictures of pointed fish that look like something from a weapons establishment, take her to more lectures by Marcus du Sautoy, buy in the services of a maths teacher, invent fish maths fun, print off two thousand worksheets, confess my ignorance, and hope basically that she just gets on with it. That one day it all clicks into place without me making it worse.

But if someone would like to tell me right now that a fishy-related degree is really all about patting rays in feeding tanks, you can be sure I'll let her know, and I'll heave a big sigh of mathematical relief.