Unequal : the math of when things do and don't add up

"Why the familiar equal sign isn't just a marker of sameness but a gateway into math's-and humanity's-most profound questions. Math is famous for its equations: 1 + 1 = 2, a2 + b2 = c2, or y = mx + b. Much of the time it can seem like that's all mathematics is: following steps to show that what's on one side of an equation is the same as what's on the other. In Unequal, Eugenia Cheng shows that's just part of the story, and the boring part to boo...