/**
 * 保留x位小数
 */
export declare function toPrecision(num: number, precision: number): number;
/**
 * 千分位
 * 100000 -> 10,000
 */
export declare function toThousands(num: number): string;
/**
 * 获得数字科学计数
 * 1000000 = 1e6
 */
export declare function toScientificNotation(num: number): string;
/**
 * 用k的方式表达
 * 1234 -> 1K
 * 12345 -> 12K
 */
export declare function toKNotation(num: number, precision?: number): string;
export declare const ifNegative: <T extends string | number | symbol>(x: any, a: T, b?: T | undefined) => T | undefined;
export declare const ifPositive: <T extends string | number | symbol>(x: any, a: T, b?: T | undefined) => T | undefined;
export declare const multi: (a: number, b: number) => number;
export declare const mid: (a: number, b?: number) => number;