Modulo returns the remainder after division. Because every value is a float64, you cannot use an integer remainder operator; instead you use the math library’s floating-point remainder, which is defined for non-integers too. 7 % 3 is 1, the familiar integer result, and 7.5 % 2 is 1.5, showing that the operator is not restricted to whole numbers.

With modulo in place, all five binary operators evaluate, plus you have the tree walk that ties them together. As with division, a modulo by zero has no meaningful answer and produces a not-a-number value for now; the errors chapter will turn that into a clear message. One prefix operator, unary minus, is still left to evaluate, and it is next.