diff --git a/operator-sum.go b/operator-sum.go
index 063364c..352e5de 100644
--- a/operator-sum.go
+++ b/operator-sum.go
@@ -56,7 +56,11 @@ func evalPlus(ctx ExprContext, self *term) (v any, err error) {
 		}
 		v = &sumList
 	} else if isFraction(leftValue) || isFraction(rightValue) {
-		v, err = sumAnyFract(leftValue, rightValue)
+		if isFloat(leftValue) || isFloat(rightValue) {
+			v = numAsFloat(leftValue) + numAsFloat(rightValue)
+		} else {
+			v, err = sumAnyFract(leftValue, rightValue)
+		}
 	} else {
 		err = self.errIncompatibleTypes(leftValue, rightValue)
 	}