We need a female Brian Cox of the maths world,” says maths teacher Mel Muldowney from Colmers School and sixth form college in Birmingham. “We need to send that positive message to girls - that you can be good at maths and be a girl.”

Increasingly, that message is beginning to get through - this year maths was the fourth most popular A level among girls, taken by more than 34,000 of them, and female students’ entries in the subject have risen by more than a fifth since 2010.

However, this success still pales in comparison with the figures for boys. For male students, maths is subject number one at A level. Almost 53,000 boys took the qualification last year and the rise in popularity over the past eight years has been even faster than for girls.

The big question remains: why, when given the chance, do 20,000 more girls than boys drop maths?

Well, it isn’t because they can’t do it. New research from assessment company Renaissance Learning shows that girls are just as good at maths as boys. The study tested 20,103 children aged 6 to 18, in 148 UK schools, on an adaptive computer-based maths practice programme, and found no significant gender gap in their achievement.

And it’s not because it is not important. Having A levels in Stem (science, technology, engineering and maths) subjects is good for earning potential - and particularly good for women’s earning potential. Women with two A levels in Stem subjects earn about 33 per cent more on average than those without, whereas for men, the boost is 7.8 per cent.

An Institute for Fiscal Studies (IFS) report published this summer found that girls knew this - 92 per cent said that pursuing jobs in Stem careers would enable them to make a good living.

So what can schools and teachers do to help girls feel confident about choosing maths?

The IFS report suggested that role models could help. And luckily for those maths teachers searching for female role models for their pupils, there are a growing number of high-profile women who are busy being brilliant at maths - and happy to talk about it.

Hannah Fry (associate professor at University College London and author of books including Hello World: how to be human in the age of the machine ), Dr Eugenia Cheng (the scientist in residence at the Institute of Chicago, who has used cakes to popularise maths) and Countdown star Rachel Riley (who demonstrates that mind-bogglingly rapid calculations can be a female trait) are all out there online as role models.

Muldowney points out that inspiring women can also be found in schools. And as a female maths teacher, she recognises her own responsibility in setting an example. When the new, tougher GCSE came out last year she didn’t just teach the exam but also sat it in solidarity with her pupils (she got a grade 9).

“I enjoyed maths and I was taught by female maths teachers,” she says. “I don’t know if it made a difference but I think there is an opportunity for schools to look at which teaching sets get female teachers.”

Muldowney suggests that if schools have maths sets where girls underperform, then a female teacher might help.

Results in primary are not a problem, with more girls than boys reaching the Department for Education’s expected standard in maths at the end of Reception, Year 2 and Year 6 (although more boys reach the higher standard at each of these points).

However, research suggests that there is still a need for stereotype-busting to start early on.

Last year, a government-commissioned report from Professor Sir Adrian Smith, then vice-chancellor of the University of London, on how to improve the take-up of maths for all pupils post-16, recognised that cultural norms were deep-seated.

The report states: “Negative attitudes towards mathematics generally are a cause for concern. Gender has a heavy influence on mathematics participation, reflecting entrenched cultural attitudes towards mathematics.” It recommends that the DfE should commission a study from preschool onwards into the root causes of these negative attitudes.

Keeping count

Teachers are starting to become more aware of the messages that girls are receiving about maths. “We have Stem days each year and look at different male and female role models so that boys and girls see the relevance of maths in the real world,” says Brooke Nolan, maths lead and Year 5 teacher at Parklands Primary in Leeds.

But the emphasis at this age is to get all children achieving and then to celebrate those achievements. After all, the main way to motivate children to do something is to help them to be good at it.

“We do a lot of maths,” says Nolan. “Children do arithmetic from 8.50am to 9.10am and then maths from 9.10am to 10.30am every day, with a 20-minute break. During the break, we mark the books, so we can do a same-day intervention with children who need it. After the break, while the teacher focuses on children who have not grasped the objectives, the rest of the children are doing more challenging work to deepen their understanding.

“We really make maths exciting, we make maths fun, so that when they move into high school, they have a love of maths.”

So if girls, and boys, find maths fun at an early age, the hope is that this could help to even things out when they make their A-level choices years later.

At the moment, by the time pupils take GCSEs, the national data for girls’ achievements in maths is starting to look less rosy. A decade ago, boys and girls were virtually neck and neck in terms of the percentage achieving A or A* grades. But since 2009, boys have started to pull ahead as linear rather than modular GCSEs were introduced, followed by new tougher, more problem-based exams.

When the IFS study looked into why girls who achieved an A or A* in maths GCSE in 2010 were far less likely to take maths A level than boys, it found that 83 per cent of girls enjoyed maths but did not like the way it was taught. They found it boring to gallop through vast amounts of content and felt less confident about doing well - despite being predicted to score highly.

Muldowney says she tailors her teaching style to make sure both boys and girls feel included. “I have to slow the boys down,” she explains. “I talk about how it’s not just about getting the answer right first, but about the journey to the answer. Boys think if they are fast they are better. That rubs off on girls.”

Nicola Whiston - Tes maths teacher of the year and head of maths at Ormiston Horizon Academy, Stoke-on-Trent - agrees that different approaches are needed. “I treat boys a bit differently and use humour,” she says. “With girls, it’s about lots and lots of confidence-building. I’ll sit down and have a small conversation about fixing a problem and then make a big deal when they have done it.

“It’s all about their self-belief. I find that it’s those girls who make the biggest progress in Year 11 - who start off feeling unconfident and build their confidence - who will often take up A level.”

This notion of progress may explain why some of the most-able girls are reluctant to choose maths. If you are a girl who gets a grade 7 in maths - but a 9 in every other subject - you have a lot of other options.

“It is not a simple issue,” says former government maths tsar Dame Celia Hoyles, now professor of maths education at the UCL Institute of Education. “Sometimes girls will do really well in a lot of subjects and they choose to do English or history. That’s a genuine choice and fair enough. But what we want to make sure is that pathways are not cut off by saying, ‘That’s not what girls do.’ We are doing a lot better than we were, but there is still that side to it.”

Teachers need to remember that students think beyond their A levels when making subject choices. The IFS study found that girls knew maths would be good for their earnings, but 67 per cent thought Stem jobs were male-dominated and the thought of being in such an environment was off-putting.

“Girls gave examples of boys chanting or making noises to intimidate them when they were asked a question by the teacher, or laughing if they gave an incorrect answer,” the report states. “Girls were particularly concerned that they would be in a class of mostly boys both at A level and university.”

Professor Andrew Noyes, of the University of Nottingham, points out that girls may also benefit from realising that taking A-level maths does not limit them to Stem careers.

“Universities need to get across the point that a lot of people are using maths in their disciplines, including social sciences,” he says. “The signalling is not strong enough. Students know they need maths to study maths, physics or engineering, but they are not really clear that it benefits them if they do psychology, biology or geography.”

He warns that while there are some things schools and universities can do, a bigger structural problem is brewing because AS-level maths entries have halved - a result of the decoupling from A level. This means that 78,000 fewer people did AS maths in 2018 than in 2017. And while a new core maths course aims to provide a post-16 qualification to run alongside A level, the take-up so far has been small, with just 6,849 entries in 2018.

“There isn’t a magic bullet,” Noyes says. “Signalling and careers talks are important but people don’t choose maths or ‘not maths’, they choose maths or something else. It is only reasonable that pupils choose their three favourite subjects - and we’re forcing students to narrow down quickly. To counter this, we would need to have a system like the Scottish Highers, Baccalaureate or Diploma system, where you could continue with five subjects.”

So while teachers can boost achievement, confidence and career aspirations, perhaps the only way to ensure more girls do maths is not to fix girls but to fix the system.

Helen Ward is a reporter for Tes

How to encourage girls to pursue maths

•  Start early - and make sure girls are represented in curriculum materials.

•  Tailor teaching - some children respond to humour, others don’t. Timed competitions can inject fun, but may backfire in certain cases, particularly if boys are pitted against girls.

•  Talk to pupils - research shows that even girls who are doing well sometimes feel less confident in their ability. A short chat can help to shift this negative thinking.

•  Talk to parents - impress on them how they can influence their children’s beliefs about what is important and possible, and what is not.

•  Use role models - getting inspiring female speakers in to talk to pupils can demonstrate to girls (and boys) that maths is very much for everyone.

•  Consider staffing - maths teachers are in short supply, but think about how female maths teachers are being used.

•  Get in touch with your local universities - maths is about more than maths. How does it help students who are thinking of studying other subjects at 18?

Source: Advice from teachers Mel Muldowney, Brooke Nolan, Nicola Whiston, and Professor Andrew Noyes