This site describes solve-engine as it is on main: 2.43.0, which npm does not have yet. npm installs 2.40.0, so a page may show an answer that version does not give yet.
ARITHMETIC_PACKAGE
const ARITHMETIC_PACKAGE: IEnginePackage;Defined in: packages/engine/src/packages/arithmetic/ArithmeticPackage.ts:15
Core arithmetic: numbers, () grouping, pi/e constants, + - * / % ^, bitwise << >> & | ^, and their *_by word forms.