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Carry (arithmetic)

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152: 322:, the second known calculator to be built, and the oldest surviving, use a different method: incrementing the digit from 0 to 9, cocks a mechanical device to store energy, and the next increment, which moves the digit from 9 to 0, releases this energy to increment the next digit by 1. Pascal used weights and gravity in his machine. Another notable machine using similar method is the highly successful 19th century 72: 395:, and must be accounted for when adding data words of lengths greater than that of the CPU. For subtractive operations, two (opposite) conventions are employed as most machines set the carry flag on borrow while some machines (such as the 6502 and the PIC) instead reset the carry flag on borrow (and vice versa). 311:. They face two basic difficulties: The first one stems from the fact that a carry can require several digits to change: in order to add 1 to 999, the machine has to increment 4 different digits. Another challenge is the fact that the carry can "develop" before the next digit finished the addition operation. 314:
Most mechanical calculators implement carry by executing a separate carry cycle after the addition itself. During the addition, each carry is "signaled" rather than performed, and during the carry cycle, the machine increments the digits above the "triggered" digits. This operation has to be
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numbers together by starting with the rightmost digits and working to the left. For example, when 6 and 7 are added to make 13, the "3" is written to the same column and the "1" is carried to the left. When used in subtraction the operation is called a
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Traditionally, carry is taught in the addition of multi-digit numbers in the 2nd or late first year of elementary school. However, since the late 20th century, many widely adopted curricula developed in the United States such as
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Some innovative machines use continuous transmission: adding 1 to any digit, advances the next one by 1/10 (which in turn advances the next one by 1/100 and so on). Some innovative early calculators, notably
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performed sequentially, starting with the ones digit, then the tens, the hundreds, and so on, since adding the carry can generate a new carry in the next digit.
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from the next digit left, and then 'paid back' by adding it to the subtrahend in the column from which it was 'borrowed', giving in this example
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implemented continuous transmission with great success, starting with the aptly named "Silent Speed" calculator. Marchant (later to become
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When several random numbers of many digits are added, the statistics of the carry digits bears an unexpected connection with
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calculator from 1870, and a design by Selling, from 1886, used this method, but neither were successful. In the early 1930,
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is also generally used to indicate borrows in subtraction, though the bit's meaning is inverted due to the effects of
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Carrying makes a few appearances in higher mathematics as well. In computing, carrying is an important function of
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Nakano, Fumihiko; Sadahiro, Taizo (February 2014), "A generalization of carries processes and Eulerian numbers",
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methods, and methods using coloring, manipulatives, and charts. Such omissions were criticized by such groups as
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which can be used as a carry-in for multiple precision arithmetic or tested and used to control execution of a
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Hegland, M.; Wheeler, W. W. (January 1997), "Linear Bijections and the Fast Fourier Transform",
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arithmetic. Normally, a carry bit value of "1" signifies that an addition overflowed the
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Mathematics under the Microscope: Notes on Cognitive Aspects of Mathematical Practice
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of digits to another column of more significant digits. It is part of the standard
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Holte, John M. (February 1997), "Carries, Combinatorics, and an Amazing Matrix",
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Carry represents one of the basic challenges facing designers and builders of
851: 824: 805: 684:; Tanny, S. (May 1973), "Significance Arithmetic: The Carrying Algorithm", 569: 79:
A typical example of carry is in the following pencil-and-paper addition:
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states that the number of carries involved in adding two numbers in base
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in the tens column. According to this method, the term "borrow" is a
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omitted instruction of the traditional carry method in favor of
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do not emphasize any specific method to find a correct answer.
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Applicable Algebra in Engineering, Communication and Computing
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deal primarily with the United States and do not represent a
71: 842: 592:"A Cohomological Viewpoint on Elementary School Arithmetic" 676: 713: 722:(June 1975), "The Real Numbers as a Wreath Product", 484: 255: 235: 261: 241: 118:from the next digit left, leaving in this example 249:is equal to the exponent of the highest power of 849: 819: 800: 555: 527: 445: 494:Bulletin of the American Mathematical Society 159:The examples and perspective in this section 75:Example: The addition of two decimal numbers 326:, which replaced the weights with springs. 177:, or create a new section, as appropriate. 737: 699: 541: 505: 462: 302: 193:Learn how and when to remove this message 786:. Charles Babbage Institute. p. 96. 141: 70: 754:"Chebyshev's continuous adding machine" 645: 589: 850: 751: 820: 801: 776: 411: 221: 590:Isaksen, Daniel C. (November 2002), 145: 66: 126:, since the ten is never paid back. 13: 14: 874: 794: 599:The American Mathematical Monthly 414:The American Mathematical Monthly 766:from the original on 2017-08-09. 150: 770: 745: 687:Journal of Combinatorial Theory 530:Advances in Applied Mathematics 516:10.1090/S0273-0979-2010-01306-9 451:Advances in Applied Mathematics 707: 670: 639: 583: 549: 521: 478: 439: 405: 1: 398: 28:that is transferred from one 739:10.1016/0001-8708(75)90115-2 701:10.1016/0097-3165(73)90013-7 368:is used in a similar sense. 345: 7: 282:riffle shuffle permutations 173:, discuss the issue on the 52:, while curricula based on 10: 881: 349: 85:7 + 9 = 16, and the digit 48:Carrying is emphasized in 543:10.1016/j.aam.2013.09.005 473:10.1016/j.aam.2009.02.002 780:The Calculating Machines 364:like an adder, the word 725:Advances in Mathematics 318:Some machines, notably 50:traditional mathematics 777:Ernst, Martin (1925). 752:Roegel, Denis (2015). 309:mechanical calculators 303:Mechanical calculators 280:and the statistics of 263: 243: 216:Mathematically Correct 76: 858:Elementary arithmetic 647:Borovik, Alexandre V. 570:10.1007/s002000050059 350:Further information: 264: 244: 142:Mathematics education 74: 18:elementary arithmetic 271:binomial coefficient 253: 233: 171:improve this section 863:Computer arithmetic 628:on January 16, 2014 360:When speaking of a 352:Adder (electronics) 336:Marchant calculator 320:Pascal's calculator 269:dividing a certain 212:invented arithmetic 137:in the tens column. 822:Weisstein, Eric W. 803:Weisstein, Eric W. 657:, pp. 87–88, 259: 239: 222:Higher mathematics 99:47 − 19 ---- 28 92:The opposite is a 82:27 + 59 ---- 86 77: 54:reform mathematics 664:978-0-8218-4761-9 262:{\displaystyle p} 242:{\displaystyle p} 203: 202: 195: 67:Manual arithmetic 870: 835: 834: 816: 815: 788: 787: 785: 774: 768: 767: 765: 758: 749: 743: 742: 741: 711: 705: 704: 703: 682:Gian-Carlo, Rota 674: 668: 667: 643: 637: 636: 635: 633: 627: 621:, archived from 596: 587: 581: 580: 553: 547: 546: 545: 525: 519: 518: 509: 482: 476: 475: 466: 443: 437: 436: 409: 389:two's complement 381:computer program 293:group cohomology 289:abstract algebra 278:Eulerian numbers 268: 266: 265: 260: 248: 246: 245: 240: 227:Kummer's theorem 198: 191: 187: 184: 178: 154: 153: 146: 136: 121: 109: 108:(10 − 9) + 7 = 8 105: 880: 879: 873: 872: 871: 869: 868: 867: 848: 847: 797: 792: 791: 783: 775: 771: 763: 756: 750: 746: 712: 708: 675: 671: 665: 644: 640: 631: 629: 625: 611:10.2307/3072368 594: 588: 584: 554: 550: 526: 522: 490:Diaconis, Persi 486:Borodin, Alexei 483: 479: 447:Diaconis, Persi 444: 440: 426:10.2307/2974981 410: 406: 401: 362:digital circuit 358: 348: 340:SCM Corporation 305: 254: 251: 250: 234: 231: 230: 224: 199: 188: 182: 179: 168: 155: 151: 144: 134: 119: 107: 103: 100: 83: 69: 12: 11: 5: 878: 877: 866: 865: 860: 846: 845: 836: 817: 796: 795:External links 793: 790: 789: 769: 744: 732:(3): 278–304, 716:Metropolis, N. 706: 694:(3): 386–421, 678:Metropolis, N. 669: 663: 638: 605:(9): 796–805, 582: 564:(2): 143–163, 548: 520: 500:(4): 639–670, 477: 457:(2): 176–196, 438: 420:(2): 138–149, 403: 402: 400: 397: 347: 344: 304: 301: 258: 238: 223: 220: 201: 200: 165:of the subject 163:worldwide view 158: 156: 149: 143: 140: 139: 138: 127: 98: 89:is the carry. 81: 68: 65: 9: 6: 4: 3: 2: 876: 875: 864: 861: 859: 856: 855: 853: 844: 840: 837: 832: 831: 826: 823: 818: 813: 812: 807: 804: 799: 798: 782: 781: 773: 762: 755: 748: 740: 735: 731: 727: 726: 721: 717: 710: 702: 697: 693: 689: 688: 683: 679: 673: 666: 660: 656: 652: 648: 642: 624: 620: 616: 612: 608: 604: 600: 593: 586: 579: 575: 571: 567: 563: 559: 552: 544: 539: 535: 531: 524: 517: 513: 508: 503: 499: 495: 491: 487: 481: 474: 470: 465: 460: 456: 452: 448: 442: 435: 431: 427: 423: 419: 415: 408: 404: 396: 394: 390: 386: 382: 378: 374: 369: 367: 363: 357: 353: 343: 341: 337: 333: 327: 325: 321: 316: 312: 310: 300: 298: 294: 290: 285: 283: 279: 274: 272: 256: 236: 228: 219: 217: 213: 209: 197: 194: 186: 176: 172: 166: 164: 157: 148: 147: 132: 128: 125: 117: 113: 112: 111: 97: 95: 90: 88: 80: 73: 64: 62: 57: 55: 51: 46: 44: 39: 35: 31: 27: 23: 19: 828: 809: 779: 772: 747: 729: 723: 718:; Ross, B.; 714:Faltin, F.; 709: 691: 690:, Series A, 685: 672: 650: 641: 630:, retrieved 623:the original 602: 598: 585: 561: 557: 551: 533: 529: 523: 497: 493: 480: 454: 450: 441: 417: 413: 407: 384: 376: 370: 365: 359: 328: 317: 313: 306: 297:real numbers 286: 275: 225: 204: 189: 183:January 2009 180: 160: 130: 115: 101: 93: 91: 84: 78: 58: 47: 42: 21: 15: 720:Rota, G.-C. 632:January 22, 383:. The same 324:Comptometer 135:4 − (1 + 1) 129:The ten is 114:The ten is 852:Categories 399:References 356:Carry flag 104:7 − 9 = −2 63:circuits. 830:MathWorld 811:MathWorld 536:: 28–43, 507:0904.3740 464:0902.0179 385:carry bit 377:carry bit 373:computers 346:Computing 332:Chebyshev 175:talk page 106:, so try 34:algorithm 839:Carrying 825:"Borrow" 761:Archived 649:(2010), 578:17603981 371:In most 169:You may 124:misnomer 96:, as in 806:"Carry" 619:3072368 434:2974981 661:  617:  576:  432:  131:copied 102:Here, 94:borrow 43:borrow 30:column 784:(PDF) 764:(PDF) 757:(PDF) 626:(PDF) 615:JSTOR 595:(PDF) 574:S2CID 502:arXiv 459:arXiv 430:JSTOR 366:carry 120:3 − 1 116:moved 61:adder 26:digit 24:is a 22:carry 843:nLab 659:ISBN 634:2014 354:and 208:TERC 20:, a 734:doi 696:doi 655:AMS 607:doi 603:109 566:doi 538:doi 512:doi 469:doi 422:doi 418:104 393:ALU 287:In 38:add 36:to 16:In 854:: 841:- 827:. 808:. 759:. 730:16 728:, 692:14 680:; 653:, 613:, 601:, 597:, 572:, 560:, 534:53 532:, 510:, 498:47 496:, 488:; 467:, 455:43 453:, 428:, 416:, 299:. 284:. 273:. 45:. 833:. 814:. 736:: 698:: 609:: 568:: 562:8 540:: 514:: 504:: 471:: 461:: 424:: 257:p 237:p 196:) 190:( 185:) 181:( 167:. 87:1

Index

elementary arithmetic
digit
column
algorithm
add
traditional mathematics
reform mathematics
adder

1
misnomer
worldwide view
improve this section
talk page
Learn how and when to remove this message
TERC
invented arithmetic
Mathematically Correct
Kummer's theorem
binomial coefficient
Eulerian numbers
riffle shuffle permutations
abstract algebra
group cohomology
real numbers
mechanical calculators
Pascal's calculator
Comptometer
Chebyshev
Marchant calculator

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