Adding and subtracting unit for a digital computer

Claim 1

AN ADDING AND SUBTRACTING UNIT FOR A DIGITAL COMPUTER COMPRISING: (A) STORAGE MEANS FOR STORING AND PROVIDING A SERIES OF OUTPUT DIGITS REPRESENTING TWO NUMBERS WHICH ARE TO BE SUBTRACTED, SAID STORAGE MEANS BEING ARRANGED FOR FIRST PROVIDING THE DIGITS BEGINNING WITH THE MOST SIGNIFICANT DIGITS OF THE TWO NUMBERS AND FOR SUBSEQUENTLY PROVIDING THE DIGITS OF THE SAME TWO NUMBERS BEGINNING WITH THE LEAST SIGNIFICANT DIGITS THEREOF AND CHARACTERIZED AS PROVIDING A DIGIT OF ONE NUMBER CONCURRENTLY WITH THE DIGIT OF THE SAME ORDER OF MAGNITUDE OF THE OTHER NUMBER; (B) MEANS FOR COMPARING THE DIGITS OF THE TWO NUMBERS AS THEY ARE FIRST PROVIDED BY THE STORAGE MEANS BEGINNING WITH THE MOST SIGNIFICANT DIGIT AND FOR PROVIDING AN INDICATION OF THE FIRST INEQUALITY DETECTED BETWEEN TWO DIGITS AND FOR PROVIDING AN INDICATION OF THE SMALLER ONE OF THE TWO DIGITS AND THEREBY IDENTIFY THE SMALLER ONE OF THE TWO NUMBERS; (C) MEANS FOR COMPLEMENTING THE SERIES OF DIGITS OF THE NUMBER PROVIDED BY THE STORAGE MEANS THE SECOND TIME WHICH IS IDENTIFIED BY INDICATION OF THE COMPARING MEANS AS THE SMALLER NUMBER AND FOR COMPLEMENTING A PREARRANGED ONE OF THE NUMBERS IF THE COMPARING MEANS INDICATES THAT ALL DIGITS OF THE TWO NUMBERS ARE EQUAL; (D) MEANS FOR COMBINING THE COMPLEMENTED DIGITS WITH THE UNCOMPLEMENTED DIGITS OF THE OTHER NUMBER PROVIDED BY THE STORAGE MEANS AND FOR PROVIDING A SERIES OF OUTPUT DIGITS CORRESPONDING TO THE TRUE DIFFERENCE BETWEEN THE TWO NUMBERS; AND (E) MEANS FOR STORING THE DIFFERENCE DIGITS IN THE ORDER IN WHICH THEY AR FORMED BY THE COMBINING MEANS UNTIL A COMPLETE NUMBER CORRESPONDING TO THE DIFFERENCE BETWEEN THE TWO NUMBERS IS STORAGED.