The trouble is, that hand is invisible. This child is not sitting at the front, nor at the back, but is stuck in the middle. This child is neither good nor bad, neither high-achieving nor struggling. This is the child you just don't see.
But, according to a new report from the Department for Education and Skills, the "invisible child" wants your attention.
"When stuck they put up their hands and waited to be noticed," the report's authors observed. "They did not mind if they did not receive immediate attention."
To avoid having to fumble around the classrooms of England, arms outstretched in search of the invisible child, a squad of school standards advisers has come up with some tips.
The advisers observed and talked to 240 pupils and their teachers at 39 schools around England. They chose schools where pupils were at risk of not improving their English and maths attainment at the critical key stage 2.
In English, the invisible child is twice as likely to be a boy.
He is generally well-behaved, displaying a positive approach to learning.
He is often bubbly, keen to respond to questions but unlikely to think first. The child usually perseveres with a set task.
In maths, the invisible child is more likely to be a well-behaved girl.
She is quiet, lacking self-confidence. She views maths as either right or wrong - and she does not like getting anything wrong. She judges how good she is by the number of ticks and crosses in her exercise books. Her work is neat.
According to one headteacher: "Teachers tell me that a lot of mothers say that they are no good at mathematics and so cannot help their children.
This is one reason for girls' underachievement."
The invisible boy and the invisible girl have one other thing in common: they have their hands up and are waiting to be noticed. So what can you do?
The school standards advisers suggest that these pupils need support in understanding personalised targets, set by the teacher.
They need opportunities to work in partnership with other pupils. And, where appropriate, the teacher should give them targeted help in small groups.
Sue Hackman, chief adviser on school standards at the department, said:
"I'm hoping that this helps teachers intervene before these pupils get fed up with school and feel they can never make progress."
Rowena Bernstein, an experienced teacher at St Michael's primary school in the north London borough of Camden, was told at the start of the year that one of her pupils was "an average student, very quiet".
"I have a very boisterous class, so this child sits back," she said.
The school is involved in the Intensive Support Programme, monitoring six pupils, of which this girl is one.
Often Mrs Bernstein operates a "no hands up" policy, to ensure discussions are not dominated by two or three children.
She has monitored the girl in several class intervention programmes, such as drama and extended writing projects, and visiting a nearby climbing wall.
Mrs Bernstein now expects the girl to attain all her targets this year.
"Even though she's still got a quiet temperament, her standards of work and learning have really risen, and her confidence has developed," she said.
"When she got to the top of the climbing wall, she got this round of spontaneous applause from the other children - and you could see her smile from the top of the wall."
* www.teachernet.gov.uk publications