Rebecca Klemm likes numbers. She likes them enough to write books and songs about them. Rebecca is the Numbers Lady, and her brainchild is Numbers Alive! an organization dedicated to improving numerical literacy for global citizenship.

Rebecca’s always been wrapped-up in numbers. She’s a statistician turned entrepreneur. We first met Rebecca handing out Pi at the Tucson Book Festival, and we were thrilled to visit her on our summer tour. While we were visiting Rebecca, she shared an idea that we think everyone should consider…

The answer to the equation 1 + 1 isn’t always 2.

As the Numbers Lady, Rebecca shares this idea a lot as she trains math teachers to “think like students” and become better instructors. Here’s the example she shared with us: 1 apple + 1 banana equals 2 pieces of fruit, UNLESS you’re a child with a banana allergy. The value of the banana is different to that child. The equation will be understood differently.

Recognizing that not all people draw the same conclusions from the same equation can help math teachers address context in mathematics, bringing it into the “real world” where life is messy, there’s lots of remainders, and values differ from person to person, culture to culture.

Take for example the Pirahã people, of northwestern Brazil. Their language has no numbers and no way of expressing numerical value. Researchers hypothesize that the Pirahã don’t need numbers because “precise counting is not culturally valued or because that value has a sufficient anumeric workaround.” 1 + 1 definitely does not equal 2 for the Pirahã.

No different than the child with banana allergies or the Pirahã, the conclusions we draw depend upon the context and values we bring to the equation.

Yet, the way we teach math and calculate ROI assumes that there is a value system, universally acceptable and indisputable.

For those of us working in the realm of social entrepreneurship, the question of value is a tricky one.

Boards and investors want “solutions that scale.” Yet, the most meaningful solutions will be those that are human-centered and contextually appropriate. Lasting change comes from solutions that can be adapted but not easily replicated like a million widgets or the next killer app.

Humans developed numeracy and mathematics to help navigate and explain our place in the world. So how do we now measure the value of work that can’t be calculated on an abacus or in a spread sheet?

Perhaps we begin by operating with the mindset that 1 + 1 might not need to equal 2.

Thanks Numbers Lady!