First, an apology to Aryabhatta. The father of Indian mathematics developed the idea of zero in our place-value system, worked out the approximation of pi, did early trig and algebra. But he’d be lost about girl math, boy math and why young people are so obsessed about it right now. Let’s clue him (and you) in.

Both terms refer to how we justify our spending behaviour these days. In August 2023, TikTok user Samantha Jane (@samjamessssss) asked her followers to refocus from Girl Dinner (the light, random foods women tend to cobble together) to Girl Math, their personal internal everyday calculations. “[If I] return something at Zara for $50 [and] bought something else for $100, it only cost me $50,” Jane explained. Users caught on immediately: Girl Math is preloading a Starbucks card and pretending the Java Chip Frappucinos are free. Girl Math is placing a bigger order just to get free shipping; otherwise, you’re kind of losing money, right?
Men joined in with Boy Math: Carrying one pair of jeans and 4 T-shirts for a week-long trip, believing that 5’9 is 5’11 with shoes on (which is basically 6’, right?), or grumbling that women are gold diggers even when you have barely three pairs of socks to your name.
Now, there’s no going back. Pet-parent Math is thinking that getting a second dog is cheaper because you already have the shampoo, bowls and food supply for the first one. Laundry Math is realising you have only half a washing load and deciding it’s sheet-washing time. We got creators, actors, musicians, chefs and artistes to share their little life-calculations. Turns out, we’re all the same inside.
Piyush Khati, 27, actor
{{/usCountry}}Now, there’s no going back. Pet-parent Math is thinking that getting a second dog is cheaper because you already have the shampoo, bowls and food supply for the first one. Laundry Math is realising you have only half a washing load and deciding it’s sheet-washing time. We got creators, actors, musicians, chefs and artistes to share their little life-calculations. Turns out, we’re all the same inside.
Piyush Khati, 27, actor
{{/usCountry}}Sale Math. “I’m quite certain of what I want vs what I need. I only give in when it’s sneakers,” says the actor who is best known for playing Dheeraj in Netflix’s Class (2023) and appears in the upcoming show Karma Calling with Raveena Tandon. Khati figures that if one pair of sneakers is at full price and the second is 50% off, they’re both on sale. Bonus points if there’s a card discount. “I will try every discount or coupon codes I can. If there’s even a little margin for bargaining, I will do it.”
Movie Math. If it’s a big movie, it must be first-day, first-show, even if it means waking up at 6am after three hours of sleep. “Even if the ticket costs twice as much. Because technically, I get an early start to the day and have a more productive one. I don’t even mind the queues. I’ll do anything for films.”
Friendship Math. For Khati, a long-distance friend is a closer pal, even though they meet once a year. “That’s usually the case when you have a small group of friends who also understand that you don’t always have the time for them, and vice-versa. There’s always a bias towards people who put in an effort, of course.”
Drinking Math. It doesn’t count as a drink if it’s a Breezer. “A beer, however, counts. But, then again, I don’t drink often.”
Vacation math. “When it comes to unique souvenirs, the budget doesn’t matter. There’s always room for local goodies on a trip, even when backpacking.” Khati has lugged back shawls and walnuts from Kashmir. He shops just short of having to pay for excess baggage.
John Oinam, 32, singer-songwriter
Concert-ticket Math. If the tickets were bought three or more months in advance, they’re basically free by the time of the gig. It means Oinam will buy refreshments and band merch guilt-free. Early-bird tickets are often around 25% cheaper. “Plus, in the months between, you also earn and save some more!”
Hair Math. “I can’t wash my hair every day because it’s damaging. Plus, I have coloured hair,” says Oinam. His routine is two days a week. “My hair looks best a day after I’ve washed it. So, if I have an event on Wednesday and another more important one on Friday, I will wash my hair on Thursday and probably wear a hat on Wednesday.
Sale Math. “If I find something I really like and it costs ₹100 but I’m getting it for ₹20, then it’s okay to spend ₹100 in total. In my head, it’s basically free.”
Relationship Math. “If you’re only meeting or getting texts after 1am, it’s a booty call. And always will be.”
Drinking Math. “Getting one LIIT is better than getting three drinks, even if it gives you a shitty hangover, because it’s cheaper.”
Travel Math. Oinam prefers travelling in a group to keep costs down. “Even if it means going with people you’re not close to. And it’s okay to overpack, because it all evens out within the group.”
Harshita Gupta, 29, comedian and content creator
Friendship Math. When a friend has just broken up “their red flags don’t matter, even if they outweigh their ex’s green flags” Gupta says. Supporting the bestie cancels out everything.
Pet-parent Math. “I get a stuffed toy for my dog Coco every time I go on a trip. It doesn’t don’t last longer than two days, but his excitement sends all the pricing math out the window.” She also believes that there’s no cap on how long one can smell their dog. “Screw Dior perfumes, this is the scent I can smell the entire day.”
Emotionally-unavailable-guy Math. “Don’t show any intensity,” in how you feel for someone who isn’t opening their heart, says Gupta. The ratio of affection must be 1:1.
Freebie Math. It’s okay to buy an unnecessary item if it comes with a freebie, even if you don’t use it. “Just don’t tell anyone that you paid that extra ₹5,000.”
Drinking Math. If there are two events in one evening, have only one drink at the first. “Or, stick to chai and make up for it at the next event.”
Travel Math. “Vacation calories don’t count. Why miss out on a cuisine if your diet is not for health reasons? And, extra outfits, particularly nightwear and lingerie, are worth paying for extra baggage.”
Ishita Mangal, 29, content creator
Sale Math. If you time it well, taking a day off to go shopping actually makes financial sense. Mangal was in the US last year and hit up the shops a day after Christmas. Everything was deeply discounted. “I bought a pair of shoes I’ve had my eye on for years. It’s a luxury item that I would never pay full price for. I did buy four pairs. But I’ve already worn all of them.”
Text-reply Math. If someone takes time to reply, don’t reply quicker. “Take as long, but not too long. If someone texts me a day late, I will reply a day after that.”
Jet-lag Math. “If you fly to the US on a night flight and stay awake on the journey, you arrive at night, get to sleep and reset yourself without a recovery day.”
Pooja Dhingra, 38, author, MasterChef judge, and owner of Le 15 Patisserie
Dessert Math. “Desserts doesn’t count when you are on your period. Calories from birthday cakes don’t count.”
Vacation Math. Overseas calories don’t count. You’re walking around a lot and are much less stressed, anyway.”
Anmol Malik, 28, singer and author
Vacation Math. “If the sightseeing tours are pre-booked, they’re basically free. Souvenir space doesn’t count as weight, because it’s cool stuff you want, anyway.”
Multiplex Math. “The popcorn you eat before the movie begins doesn’t count. There’s always room for more popcorn inside the theatre.”
Paying-bills Math. “If I go out to eat with a small group of my girlfriends and pay the whole bill, and then they pay me back, then I’ve basically made money. The math doesn’t add up, but it sure feels like it.”