The broadcaster and presenter Rachel Riley has a sunny personality which manifests itself in encouragement — even if she privately thinks you are making a mess of things.

Thus, when we meet via Zoom and I confess to her that I got stuck at trigonometry in her debut mathematics primer, At Sixes And Sevens — aimed at adults — Riley is relentlessly upbeat. “Well done!” she says, possibly the only “well done” I have ever had in my life about maths. “Well done! Trig is the hardest part! If you got as far as trig, you were doing really well!”

And that, perhaps, is Riley’s secret: her seemingly joyous approach to life. If there’s a problem, she works around it, unpicks it, deals with it until it is manageable. Along the way she kindly chivvies and cheers people on, until, perhaps, they are convinced of the truth of her “can-do” attitude.

In fact, she says, “I’m hoping my book will give people more confidence in themselves and their abilities with maths. The inspiration behind doing it: I often get friends or family sending me messages on social media and asking about problems. Perhaps they’ve been trying to help their kids and they don’t understand the maths. I’ve always really liked answering. When you learn stuff in school, you might just have been doing it to pass exams — and now, of course, you don’t remember”.

But armed with a copy of At Sixes And Sevens, many adults may well find their ability to figure out the figures coming back.

Riley is good-naturedly aware that many people ask about the practical uses of maths in adult life. She writes: “I’ve never had much use for the poems of Sylvia Plath, but no one ever questioned the English teacher for making us dissect her every word”. What she calls “poor old maths”, however, gets a bum rap, with people “almost wearing it as a badge of honour” that they are mathematically illiterate.

Good numeracy, Riley points out, is linked to “employability, to better earnings”, and poor numeracy often links to “poor health and mental health problems”. So there are any amount of incentives for coming to grips with maths, she says, and perhaps, I think, having spoken to her, it’s the teaching that is at fault, which leads to so many saying that their brains “are not wired” for numbers. Had I had a teacher such as Riley, urging me on from the sidelines, you can do it, you can do it, I am sure I would be better than I am at maths.

She links the subject with music, writing: “Maths, like music, is a truly universal language — so, once you learn it, you can read anything written in it, no matter the origin of the person who wrote it”. I wondered then, given that musicians say everyone can be taught to sing, whether Riley believed everyone could “get” maths. She laughs, but responds: “In the same way that not everyone who learns to carry a tune is going to be Pavarotti, not everyone [with maths] is going to be Stephen Hawking. But everyone can make progress from the position in which they started”.

Rachel Riley is a British “personality”, in the public eye and generally cherished for her likeability. She is famous as the maths whizz on the Countdown TV programme, which catapulted her to a 2013 appearance on Strictly Come Dancing.

It was on that programme that she met her husband, the professional dancer Pasha Kovalev — the couple married in 2019. They are now besotted parents to daughter Maven Aria, and Riley was, when we spoke, due to give birth to their second child “any day now”.

She is also a presenter — with comedian Jimmy Carr — on the spin-off programme, 8 Out Of 10 Cats Does Countdown, and expanding on her passion for football, particularly her favourite club, Manchester United, has fronted several football programmes as a pundit.

With this full-on career, a busy family life — oh, and learning Russian in order to be able to talk to Pasha’s family — one might have thought that Riley had a very full plate.

But, much to the surprise of many, at the height of the Corbyn era, Riley decided to fight online antisemitism as well, and became notorious on social media for taking on the keyboard warriors and giving as good as she got. The surprise was all the more because few people even knew she was Jewish — her mother is, her father is not — and she has often jokingly referred to her Manchester United fandom as her “religion”.

But she certainly identifies culturally as Jewish and waded into the antisemitism wars with typical passion, becoming, in the process, an ambassador for the Centre for Countering Digital Hate. She didn’t just attack the trolls on line: she made a point of learning about the issue and is currently waiting for judgment in a case she brought against Laura Murray, former adviser to Jeremy Corbyn.

Now that Corbyn is no longer leader of the Labour Party, did Riley think the war against antisemitism was over? She smiles. “There’s always going to be antisemitism, and sadly we are seeing a rise in it. For my part, I didn’t want an antisemitic government and there was a huge sigh of relief on 13 December 2019 [the day after the General Election] when the British public rejected the Labour Party under Corbyn. I had my daughter two days later; I think Keir Starmer has some really good people around him whom I met on the way, proper Labour people opposed to Labour antisemitism. I do feel it’s less my fight now, and more theirs in terms of salvaging the party”.

Riley notes, however, in her role with the Centre for Countering Digital Hate — of which she is “immensely proud” — that there is “so much overlap between anti-vaxers, conspiracy theorists, and antisemitism. The work the Centre is doing [in identifying such threats] is invaluable”.

As for her and Pasha’s adored daughter, formally Maven Aria Riley Kovaleva, her name, Riley explains, “is a nod to my Jewish heritage. Maven means one who understands, and Aria is from the Hebrew for lioness. But also the initials spell out ‘Mark’, because my uncle died while I was pregnant, so that’s a way of honouring him.”

Laughing, she said she and her husband had some private ideas for the name of their second child but were not yet ready to share them.

Riley knows she will have her hands full, with her maths book to promote, two tiny children to look after, and the prospect of returning to Countdown, which she has been working on for 13 years, and aims to stay with as long as she can.

Just the same, she says, she really enjoyed the process of doing the book and is now thinking about what might be her next project —perhaps maths again, but this time for children and teenagers.

It’s only when I am listening to the tape of our conversation that I am brought up short by Riley’s confession that even though she loved maths at school — and went on to study it in depth at Oxford — she found maths lessons “boring”. Not boring because she could whizz through the problems, but boring because the books and the teaching were “unimaginative. We weren’t given the tools to problem-solve in a holistic way”.

Maths, maintains Riley, has almost infinite applications — from time travel for astronauts, to helping people to decorate their house by calculating the numbers of tiles or rolls of wallpaper. And, with a final grin, she wishes me “Shabbat shalom” and admits that “all the bad puns in At Sixes and Sevens are my own.”

At Sixes and Sevens, by Rachel Riley, is published this week by Harper Collins