US Patent 7218247 Brief numerical keypad and its output method

A brief numerical keypad is constructed to include four number keys aligned in X-axis and Y-axis directions and abutted against one another, each expressing one of the numbers from 1˜9, a plurality of double-bridging operation portions respectively bridging the abutted area of each two adjacent number keys, each double-bridging operation portion expressing a number equal to the sum of the numerals of the respective two abutted number keys, and a plurality of triple-bridging operation portions respectively bridging the abutted area of each three adjacent number keys, each triple-bridging operation portion expressing a number equal to the sum of the numerals of the respective three abutted number keys.