3 Ways to Make Math Work for You (Not Against You)
Is math a form of self-defense? Bentley’s Noah Giansiracusa thinks so.
In his new book, “Robin Hood Math: Take Control of the Algorithms That Run Your Life,” the associate professor of Mathematical Sciences explains how we’re nudged, ranked, targeted and persuaded daily by numbers we didn’t choose and formulas we never see.
From credit scores and product rankings to online search results and social media feeds, he says, financial companies and Big Tech use math to keep us scrolling and spending — and boosting their bottom lines.
Consumers can fight back, Giansiracusa says, by meeting algorithmic power with mathematical literacy. “Math is commonly portrayed as something only prodigies and savants can do,” he explains. “But ordinary people can use simple math formulas to confront everyday challenges.”
His book shows readers how to do just that, reclaiming the power of math to protect their time, money and attention in an increasingly data-driven world.
Mathematics and Manipulation
“In today’s digital economy, everything we do is tracked, packaged as data and sold to the highest bidder,” Giansiracusa explains. This happens through a process known as numerification, which assigns numerical values to human activity. Once quantified, this data is fed into algorithms that help companies predict — and profit from — consumer behavior at an unprecedented scale.
The first step toward reclaiming our humanity and autonomy, he says, is understanding how companies use common mathematical concepts like weighted sums and expected value to manipulate us.
In “Robin Hood Math,” Giansiracusa explains these concepts and offers practical strategies readers can use to take back their power.
#1: Understand the Math Behind Your Credit Score
Few numbers shape adult life as powerfully as our consumer credit scores. These three-digit numbers affect our ability to rent an apartment, buy a home and finance a car. And yet, many consumers treat them as mysterious moral judgments rather than what they are: mathematical formulas.
Credit scores are calculated using weighted sums, Giansiracusa explains. Different financial behaviors are assigned specific values (V) and combined into a single number based on how heavily each behavior is weighted (W):
Score = (W₁ × Vbehavior₁) + (W₂ × Vbehavior₂) + (W₃ × Vbehavior₃)
For example, the formula used by FICO — the credit score brand used by 90% of U.S. lenders — gives payment history (35%) and total amount of debt (30%) the heaviest weights. Other factors, like length of credit history (15%), new credit (10%) and types of credit (10%) contribute smaller portions to the final score.
Score = (.35 × Vpayment history) + (.30 × Vdebt)
+ (.15 × Vcredit history) + (.10 × Vnew credit)
+ (.10 × Vcredit mix)
The result feels objective and authoritative — but that impression is misleading. “People want to believe that data implies rigor and impartiality,” Giansiracusa notes. In reality, human judgment and institutional priorities determine which behaviors matter most and how heavily they’re weighted.
Once consumers understand how the formula is structured, Giansiracusa says, they can use it strategically, by focusing more on paying down balances than closing accounts, for example. As he notes: “The math doesn’t change — but once you understand it, the balance of power does.”
#2: Train Your Social Media Feed
Facebook. Instagram. TikTok. X. Each time you open a social media platform, an algorithm decides which posts will appear in your feed. “Most users scroll through only the first handful of posts, so the order the algorithm comes up with matters a lot,” Giansiracusa explains.
Like credit scores, these algorithms use weighted sums, assigning different values to various engagement actions. They also rely on expected value, which multiplies the value of an outcome by its likelihood of happening:
Expected value = (value of outcome) x (probability of outcome)
For example, liking or sharing a post might count as one point, while leaving a comment could be worth three and watching a video five. The values (V) are multiplied by the probability (P) of a user engaging in that behavior, based on the individual’s previous interactions on the platform:
Score = (Vlike × Plike) + (Vshare × Pshare) +
(Vcomment × Pcomment) + (Vwatch × Pwatch)
The underlying formula is the same for everyone, but the results are highly personalized.
If you don’t like what you currently see, Giansiracusa says, you can game the algorithm and curate your feed. Doing so requires “restraint and intentionality,” he cautions. If a post makes you angry, “resist the temptation to comment and simply scroll on by. Don’t give the algorithm the points it’s trying to manipulate you into providing.”
#3: See Through Online Advertising Tricks
“You might think of Google as a search engine, but nearly 80% of its $300 billion annual revenue comes from ads — both hosting them and placing them throughout the Internet,” Giansiracusa explains. That’s an important distinction, and one that explains why Google search results feature more ads and sponsored content now than ever before.
The company’s priority is no longer helping users find high-quality information as quickly as possible, he says. It’s keeping users online for as long as possible to maximize the number of ads they see — and the amount of ad revenue Google earns.
Consumers experience a similar situation while searching for products on Amazon. The e-commerce titan “has been filling its site with sponsored content and sneakily driving customers to Amazon-owned brands or corporate partners, whose products are often overpriced and of lower quality,” Giansiracusa shares.
Instead of providing organic search results earned through ratings, reviews and sales, the company offers premium product placement to the highest bidder. According to one study, customers had to scroll down to the 17th item in the default “Featured” rankings to find the best deal. Small wonder, then, that sponsored ads account for nearly 80% of Amazon’s $40 billion in annual ad revenue.
How can consumers defend themselves against these algorithmic incentives? For Google users, “clicking the Web tab at the top of a search gets rid of the AI summaries, sponsored links and other clutter,” he shares. Amazon users can use the drop-down menu to switch results from the default “Featured” ranking to another option, like average customer review or lowest-to-highest price.
The Limits of Gaming the Algorithm
While algorithmic hacks like these can help customers in the short term, Giansiracusa believes that legislation is the only way to end this kind of market manipulation. That’s because these tech giants have become so large and so powerful, and so central to our lives, we’ve become a captive audience. “When you’re the only game in town, you set the rules with impunity and make sure you’re the winner — even when doing so means your customers are the losers,” he says.
Until consumers get help from lawmakers, Giansiracusa argues, we can use math to stand up for ourselves and claw back some of our power: “In a society that all too often takes from the poor and gives to the rich, math can be a vital democratizing force.”