Diary of a Primary School Mum: 'The pièce de résistance was an African xylophone'

"Mummy," asks Claire, "is this how we should hold scissors to be safe?" "Yes, darling," I concur, without even a cursory glance. Suddenly, guilt seeps in – scissors are a dangerous weapon – and I look up from the newspaper to find Claire walking around, little fist clamping the blades tight shut. "Oh no," I say, running over, "I think maybe this would be a better way to hold them." I move her fingers to the handles, sharp edges pointing downwards. Claire looks at me as if I am insane and switches her grip straight back. "Miss Perry says that you should do it like this and she should know. She's a teacher."

No need to add salt to the wound. Not everyone is cut out to teach – a fact that came into focus yesterday when I volunteered to share my musical-instrument collection with reception as part of International Arts Week. It began with 30 pairs of eyes intrigued by the display of drums and flutes. The pièce de résistance, a wooden xylophone from Africa, prompted much excitement. "This comes from a country that begins with a 'Z'," I told them. Claire stuck up her hand. "Mummy, my water bottle's not working properly. Can you repair it?" I ignored her. "When Claire and Oliver try to think of words beginning with 'Z'," I continued, "there are never very many they can think of. But a couple of countries in Africa start with that letter. Does anyone have any ideas?" Oliver strained his arm to the ceiling. "Zoo?" he offered.

We discussed Zambia and Zimbabwe and how Africa has a monopoly on countries beginning with that elusive letter – good teaching, I thought; but then it came to what actually to do with the instruments. With only 14 on offer and 30 pupils in the class, the sums didn't compute and kids started to get tetchy. Then Plan B (making a lily out of a napkin) kicked in. "Does anyone know what origami is?" "Yes," shouted one boy, "it's something nice to eat." "Actually," I corrected, dishing out napkins, "it's the Japanese art of paper folding."

My husband said that it wouldn't work, they'd never be able to make the flowers. What he hadn't predicted was that neither would I. So nervous and fumble-fingered had I become, that the first two attempts failed completely and by the time success arrived on stab three, the bell went and it was going-home time. "You should have prepared better," my husband said later. "And taken in a 'Here's one I made earlier' flower for every child."

Failure is contagious. The next afternoon, my "How was your day?" question (normally met with upbeat superlatives) received a "not so good" reply from my daughter. "Why? What was wrong?" "I had an adding and subtracting lesson with a teacher, not Miss Perry, and I couldn't get the answer right, so she shouted at me. That wasn't kind, was it?" There was no pause for breath. "And it got worse," Claire gesticulated maniacally. "We were told that the children who sat nicest with hands on their laps would get to make some dough, but I sat beautifully and did*'t get picked. It's not fair."

Being picked last for netball and spectacular incompetence at all things mathematical (sums didn't compute, even back then) plagued my secondary years. It was hard enough in lessons aged 13, let alone five. I want to cosset my children a while longer, so the next morning I ask Miss Perry that if more dough is to be made, could Claire be considered. "And ask her the other thing," Claire nudged. "What other thing?" "Ask Miss Perry if she wants to come round to our house on a play date."