The final project in my calculus class was to write an essay about the real-world application of some concept we had learned in the course.

I liked that. What better way to integrate my learning than to think about its implications in everyday life?

I didn’t have to think far. I wrote about my favorite function, the maxima-minima.

The maxima-minima function is used to solve problems like: What is the lowest price I should charge for an item to make the maximum profit? What is the fastest I can drive my car and still achieve the best gas mileage? When building a house, what are the ideal dimensions to use the least possible amount of building materials?I didn’t have to think far

Problems like these so perfectly encapsulate the basic dilemma of life. Every decision involves a tradeoff of some sort. I must give up something that I want in order to get something else. Speed versus efficiency. Safety versus convenience. Quality versus quantity. Short-term pleasure versus long-term health. We make these decisions consciously or unconsciously dozens of times per day, whenever we choose how to allocate our time, money or other resources. What is the least I must give up to get the most of what I want?

In this week’s Torah portion, we find the mitzvah of aser te’aser, literally translated as “Tithe you shall tithe,” referring to the obligation to set aside a tenth of our earnings for charity.1 Since the word for “tithing,” aser, has the same root as “wealthy,” ashir, the Talmud interprets this verse as “Tithe in order that you shall become wealthy.”2

Now, that sure defies all the laws of calculus and economics! If I give up a tenth of my earnings to charity, then obviously there is a tenth less for me—a tenth less for me to invest or to spend on any of my needs.

But the true value of money depends on so many variables that we can neither predict nor control. Will my investments succeed or fail? Will I derive satisfaction from my earnings, or will my money go toward medical bills, legal expenses or other aggravations? Even if I have enough money to enjoy the tangible pleasures of life—a nice car, fine dining, vacations—will I have enough of the intangibles, such as strong relationships and meaningful goals, to make it all seem worthwhile?

What am I really giving up by tithing? I think what we are most afraid of is not giving up our money but giving up control. When I choose to buy a car, I can do research; I can even plug in my maxima-minima functions to find the best possible car at the lowest possible price within my budget. Once I buy the car, I can trade it in, sell it or upgrade it, and I can buy insurance to offset any possible loss or damage.

But giving tzedakah, charity, has no such guarantee. I am giving up something that I earned through the sweat of my own brow, to be enjoyed by someone else who didn’t put the same effort into it. Once I give up the money, it’s gone—I have no further say in how it will be spent (unless I want to be an insufferable control freak). This is why the book of Tanya states that giving charity is equivalent to all other mitzvahs.3 While other mitzvahs might use a specific part of the body (tefillin on the hand and head, for example), charity involves giving money that we earned with our time, talent and expertise, money that we could have used for any of our human needs. Giving up our money is the closest we can come to giving up ourselves.

So, what is the maximum amount of money I should give up for What I receive in return has no minimum or maximumcharity, and what do I get in return? Jewish law is clear on the minimum and maximum recommended amounts to give to charity: not less than one-tenth and not more than one-fifth of your income. (In some situations, it may be appropriate to give more or less than these amounts; a rav should be consulted.)

But what I receive in return has no minimum or maximum. It is truly infinite. It is a Divine promise for success in our endeavors—success that will give us the ability to truly enjoy and make use of the bounty we are given. G‑d even invites us to challenge Him with the mitzvah of charity, to see if the money we tithe is repaid. “Please, test me with this,” says G‑d.4

The concept of tzedakah is especially pertinent now, when we are in the seven-week consolation period following the Jewish day of mourning on the 9th of Av. “Zion will be redeemed with justice, and its captives with charity.”5 Giving tzedakah is a unique opportunity to bring holiness and blessing into every aspect of our lives, and thereby merit the ultimate redemption.