export declare const add: (a: any, b: any) => any;
export declare const subtract: (a: any, b: any) => number;
export declare const multiply: (a: any, b: any) => number;
export declare const divide: (a: any, b: any) => number;
export declare const sum: (arr: any[]) => any;
export declare const mean: (arr: any[]) => number;