Knowledge (XXG)

Irreducible fraction

Source ๐Ÿ“

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over a field. The irreducible fraction for a given element is unique up to multiplication of denominator and numerator by the same invertible element. In the case of the rational numbers this means that any number has two irreducible fractions, related by a change of sign of both numerator and
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Which method is faster "by hand" depends on the fraction and the ease with which common factors are spotted. In case a denominator and numerator remain that are too large to ensure they are coprime by inspection, a greatest common divisor computation is needed anyway to ensure the fraction is
466: 543: 837:: any element of such a field can be written as a fraction in which denominator and numerator are coprime, by dividing both by their greatest common divisor. This applies notably to 395:
A fraction that is reducible can be reduced by dividing both the numerator and denominator by a common factor. It can be fully reduced to lowest terms if both are divided by their
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denominator; this ambiguity can be removed by requiring the denominator to be positive. In the case of rational functions the denominator could similarly be required to be a
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can be used. The Euclidean algorithm is commonly preferred because it allows one to reduce fractions with numerators and denominators too large to be easily factored.
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In the first step both numbers were divided by 10, which is a factor common to both 120 and 90. In the second step, they were divided by 3. The final result,
1006: 858:, an erroneous arithmetic procedure that produces the correct irreducible fraction by cancelling digits of the original unreduced form. 1121: 418: 1068: 1041: 1014: 983: 918: 594: 1335: 1340: 1114: 975: 893: 888: 834: 508: 940:, College text books, Sandhurst. Royal Military College, vol. 1, Longman, Brown, Green, and Longmans, p. 75 1294: 861: 687:
The fact that any rational number has a unique representation as an irreducible fraction is utilized in various
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could be represented as a ratio of integers, then it would have in particular the fully reduced representation
1282: 491: 396: 99: 1164: 855: 818: 47: 821:, so the premise that the square root of two has a representation as the ratio of two integers is false. 404: 400: 1240: 1225: 830: 1255: 1089: 1064: 1058: 1037: 1031: 1010: 979: 969: 914: 908: 883: 838: 111: 1000: 1299: 843: 688: 122:
can be represented as an irreducible fraction with positive denominator in exactly one way.
1289: 1250: 119: 267: 212: 1329: 1314: 1235: 1092: 1265: 1260: 1230: 1063:, Graduate Texts in Mathematics, vol. 242, Springer, Lemma 9.2, p. 183, 487:, is an irreducible fraction because 4 and 3 have no common factors other than 1. 58:
than 1 (and โˆ’1, when negative numbers are considered). In other words, a fraction
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The original fraction could have also been reduced in a single step by using the
115: 103: 647:, and so both sides of the latter must share the same prime factorization, yet 561:
representation as an irreducible fraction with a positive denominator (however
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Elements of Arithmetic and Algebra: For the Use of the Royal Military College
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is greater than 1), the latter is a ratio of two smaller integers. This is a
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The Legacy of Niels Henrik Abel: The Abel Bicentennial, Oslo, June 3-8, 2002
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and of other irrational numbers. For example, one proof notes that if
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although both are irreducible). Uniqueness is a consequence of the
1141: 461:{\displaystyle {\frac {120}{90}}={\frac {12}{9}}={\frac {4}{3}}} 1110: 153:
is irreducible if and only if there is no other equal fraction
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Integers, Fractions, and Arithmetic: A Guide for Teachers
864:, the approximation of real numbers by rational numbers. 114:
such that the numerator and the denominator are coprime
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The notion of irreducible fraction generalizes to the
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share no prime factors so the set of prime factors of
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proofs of the irrationality of the square root of 2
328:are all irreducible fractions. On the other hand, 537: 460: 125:An equivalent definition is sometimes useful: if 1005:, Mathematical Association of America Textbooks, 538:{\displaystyle {\frac {120}{90}}={\frac {4}{3}}} 1122: 8: 659:(with multiplicity) is a subset of those of 907:Laudal, Olav Arnfinn; Piene, Ragni (2004), 344:is reducible since it is equal in value to 50:in which the numerator and denominator are 1129: 1115: 1107: 726:are the smallest possible; but given that 525: 512: 510: 448: 435: 422: 420: 931: 929: 874: 951: 7: 1007:Mathematical Association of America 782:(since cross-multiplying this with 999:Cuoco, Al; Rotman, Joseph (2013), 802:shows that they are equal). Since 25: 1181: 1150: 1057:Grillet, Pierre Antoine (2007), 133:are integers, then the fraction 494:of 90 and 120, which is 30. As 376:is less than the numerator of 78:is irreducible if and only if 1: 976:American Mathematical Society 557:Every rational number has a 889:Encyclopedia of Mathematics 835:unique factorization domain 1357: 1036:, CRC Press, p. 183, 595:unique prime factorization 54:that have no other common 1221: 1179: 1148: 1030:Garrett, Paul B. (2007), 913:, Springer, p. 155, 882:Stepanov, S. A. (2001) , 862:Diophantine approximation 671:and by the same argument 27:Fully simplified fraction 663:and vice versa, meaning 36:fraction in lowest terms 1336:Fractions (mathematics) 1002:Learning Modern Algebra 936:Scott, William (1844), 492:greatest common divisor 397:greatest common divisor 360:, and the numerator of 100:greatest common divisor 856:Anomalous cancellation 549:actually irreducible. 539: 462: 1341:Elementary arithmetic 540: 463: 978:, pp. 131โ€“134, 839:rational expressions 509: 419: 110:" may also refer to 108:irreducible fraction 32:irreducible fraction 597:of integers, since 405:prime factorization 401:Euclidean algorithm 1158:Division and ratio 1093:"Reduced Fraction" 1090:Weisstein, Eric W. 966:Sally, Paul J. Jr. 964:Sally, Judith D.; 831:field of fractions 535: 458: 197:| < | 181:| < | 112:rational fractions 1323: 1322: 533: 520: 456: 443: 430: 219:. (Two fractions 211:| means the 16:(Redirected from 1348: 1300:Musical interval 1213: 1212: 1210: 1209: 1206: 1203: 1185: 1184: 1154: 1131: 1124: 1117: 1108: 1103: 1102: 1075: 1073: 1060:Abstract Algebra 1054: 1048: 1046: 1033:Abstract Algebra 1027: 1021: 1019: 996: 990: 988: 961: 955: 949: 943: 941: 933: 924: 923: 903: 897: 896: 879: 844:monic polynomial 816: 815: 806: >  801: 799: 798: 793: 790: 781: 779: 778: 769: 766: 752: 751: 745: 743: 742: 737: 734: 717: 715: 714: 709: 706: 697: 696: 638: 637: 635: 634: 629: 626: 617: 615: 614: 609: 606: 592: 590: 589: 586: 583: 576: 574: 573: 570: 567: 544: 542: 541: 536: 534: 526: 521: 513: 501: 497: 486: 484: 483: 480: 477: 467: 465: 464: 459: 457: 449: 444: 436: 431: 423: 391: 389: 388: 385: 382: 375: 373: 372: 369: 366: 359: 357: 356: 353: 350: 343: 341: 340: 337: 334: 327: 325: 324: 321: 318: 311: 309: 308: 305: 302: 295: 293: 292: 289: 286: 258: 256: 255: 250: 247: 238: 236: 235: 230: 227: 210: 204: 202: 196: 188: 186: 180: 172: 170: 169: 164: 161: 152: 150: 149: 144: 141: 102:of 1. In higher 77: 75: 74: 69: 66: 44:reduced fraction 21: 1356: 1355: 1351: 1350: 1349: 1347: 1346: 1345: 1326: 1325: 1324: 1319: 1290:Just intonation 1217: 1207: 1204: 1201: 1200: 1198: 1197: 1186: 1182: 1177: 1155: 1144: 1135: 1088: 1087: 1084: 1079: 1078: 1071: 1056: 1055: 1051: 1044: 1029: 1028: 1024: 1017: 998: 997: 993: 986: 963: 962: 958: 950: 946: 935: 934: 927: 921: 906: 904: 900: 881: 880: 876: 871: 852: 827: 813: 811: 794: 791: 786: 785: 783: 770: 767: 757: 756: 754: 749: 747: 738: 735: 730: 729: 727: 710: 707: 702: 701: 699: 694: 692: 685: 630: 627: 622: 621: 619: 610: 607: 602: 601: 599: 598: 587: 584: 581: 580: 578: 571: 568: 565: 564: 562: 555: 507: 506: 499: 495: 481: 478: 475: 474: 472: 417: 416: 413: 386: 383: 380: 379: 377: 370: 367: 364: 363: 361: 354: 351: 348: 347: 345: 338: 335: 332: 331: 329: 322: 319: 316: 315: 313: 306: 303: 300: 299: 297: 290: 287: 284: 283: 281: 251: 248: 243: 242: 240: 231: 228: 223: 222: 220: 206: 198: 192: 190: 182: 176: 174: 165: 162: 157: 156: 154: 145: 142: 137: 136: 134: 120:rational number 70: 67: 62: 61: 59: 28: 23: 22: 15: 12: 11: 5: 1354: 1352: 1344: 1343: 1338: 1328: 1327: 1321: 1320: 1318: 1317: 1312: 1307: 1302: 1297: 1292: 1287: 1286: 1285: 1275: 1270: 1269: 1268: 1258: 1253: 1248: 1243: 1238: 1233: 1228: 1222: 1219: 1218: 1216: 1215: 1194: 1192: 1188: 1187: 1180: 1178: 1176: 1175: 1161: 1159: 1156: 1149: 1146: 1145: 1136: 1134: 1133: 1126: 1119: 1111: 1105: 1104: 1083: 1082:External links 1080: 1077: 1076: 1069: 1049: 1042: 1022: 1015: 1009:, p. 33, 991: 984: 956: 944: 925: 919: 898: 873: 872: 870: 867: 866: 865: 859: 851: 848: 826: 825:Generalization 823: 684: 681: 554: 551: 546: 545: 532: 529: 524: 519: 516: 469: 468: 455: 452: 447: 442: 439: 434: 429: 426: 412: 409: 268:if and only if 213:absolute value 205:, where | 90:, that is, if 26: 24: 14: 13: 10: 9: 6: 4: 3: 2: 1353: 1342: 1339: 1337: 1334: 1333: 1331: 1316: 1313: 1311: 1308: 1306: 1303: 1301: 1298: 1296: 1293: 1291: 1288: 1284: 1281: 1280: 1279: 1276: 1274: 1271: 1267: 1264: 1263: 1262: 1259: 1257: 1254: 1252: 1249: 1247: 1244: 1242: 1239: 1237: 1234: 1232: 1229: 1227: 1224: 1223: 1220: 1196: 1195: 1193: 1189: 1174: 1170: 1166: 1163: 1162: 1160: 1153: 1147: 1143: 1139: 1132: 1127: 1125: 1120: 1118: 1113: 1112: 1109: 1100: 1099: 1094: 1091: 1086: 1085: 1081: 1072: 1070:9780387715681 1066: 1062: 1061: 1053: 1050: 1045: 1043:9781584886907 1039: 1035: 1034: 1026: 1023: 1018: 1016:9781939512017 1012: 1008: 1004: 1003: 995: 992: 987: 985:9780821887981 981: 977: 973: 972: 967: 960: 957: 954:, p. 74. 953: 948: 945: 939: 932: 930: 926: 922: 920:9783540438267 916: 912: 911: 902: 899: 895: 891: 890: 885: 878: 875: 868: 863: 860: 857: 854: 853: 849: 847: 845: 840: 836: 832: 824: 822: 820: 819:contradiction 809: 805: 797: 789: 777: 773: 765: 761: 741: 733: 725: 721: 713: 705: 690: 682: 680: 678: 675: =  674: 670: 667: =  666: 662: 658: 654: 650: 646: 643: =  642: 633: 625: 613: 605: 596: 560: 552: 550: 530: 527: 522: 517: 514: 505: 504: 503: 493: 488: 453: 450: 445: 440: 437: 432: 427: 424: 415: 414: 410: 408: 406: 402: 398: 393: 280:For example, 278: 276: 273: =  272: 269: 266: 262: 254: 246: 234: 226: 218: 214: 209: 201: 195: 185: 179: 168: 160: 148: 140: 132: 128: 123: 121: 117: 113: 109: 105: 101: 97: 93: 89: 85: 81: 73: 65: 57: 53: 49: 45: 41: 40:simplest form 37: 33: 19: 1277: 1096: 1059: 1052: 1032: 1025: 1001: 994: 970: 959: 952:Scott (1844) 947: 937: 909: 901: 887: 877: 828: 807: 803: 795: 787: 775: 771: 763: 759: 739: 731: 723: 719: 711: 703: 686: 683:Applications 676: 672: 668: 664: 660: 656: 652: 648: 644: 640: 631: 623: 611: 603: 558: 556: 547: 496:120 รท 30 = 4 489: 470: 394: 279: 274: 270: 264: 260: 252: 244: 232: 224: 216: 207: 199: 193: 183: 177: 166: 158: 146: 138: 130: 126: 124: 107: 95: 91: 83: 79: 71: 63: 43: 39: 35: 31: 29: 18:Lowest terms 1278:Irreducible 1208:Denominator 502:, one gets 500:90 รท 30 = 3 116:polynomials 104:mathematics 1330:Categories 1310:Percentage 1305:Paper size 1214:= Quotient 905:E.g., see 884:"Fraction" 869:References 753:, so does 553:Uniqueness 265:equivalent 173:such that 1283:Reduction 1241:Continued 1226:Algebraic 1202:Numerator 1138:Fractions 1098:MathWorld 894:EMS Press 810:(because 1256:Egyptian 1191:Fraction 1173:Quotient 1165:Dividend 850:See also 639:implies 411:Examples 118:. Every 56:divisors 52:integers 48:fraction 1273:Integer 1246:Decimal 1211:⁠ 1199:⁠ 1169:Divisor 833:of any 812:√ 800:⁠ 784:⁠ 780:⁠ 755:⁠ 748:√ 746:equals 744:⁠ 728:⁠ 716:⁠ 700:⁠ 693:√ 636:⁠ 620:⁠ 616:⁠ 600:⁠ 591:⁠ 579:⁠ 575:⁠ 563:⁠ 498:, and 485:⁠ 473:⁠ 390:⁠ 378:⁠ 374:⁠ 362:⁠ 358:⁠ 346:⁠ 342:⁠ 330:⁠ 326:⁠ 314:⁠ 310:⁠ 298:⁠ 294:⁠ 282:⁠ 257:⁠ 241:⁠ 237:⁠ 221:⁠ 171:⁠ 155:⁠ 151:⁠ 135:⁠ 98:have a 88:coprime 76:⁠ 60:⁠ 46:) is a 1266:Silver 1261:Golden 1251:Dyadic 1236:Binary 1231:Aspect 1142:ratios 1067:  1040:  1013:  982:  917:  718:where 559:unique 312:, and 203:| 191:| 187:| 175:| 261:equal 1315:Unit 1140:and 1065:ISBN 1038:ISBN 1011:ISBN 980:ISBN 915:ISBN 722:and 651:and 317:โˆ’101 259:are 239:and 129:and 94:and 86:are 82:and 34:(or 1295:LCD 515:120 425:120 403:or 323:100 277:.) 263:or 215:of 189:or 106:, " 42:or 30:An 1332:: 1171:= 1167:รท 1095:. 928:^ 892:, 886:, 846:. 774:โˆ’ 762:โˆ’ 679:. 645:bc 641:ad 618:= 588:โˆ’3 582:โˆ’2 577:= 518:90 438:12 428:90 392:. 296:, 275:bc 271:ad 38:, 1205:/ 1130:e 1123:t 1116:v 1101:. 1074:. 1047:. 1020:. 989:. 942:. 814:2 808:b 804:a 796:b 792:/ 788:a 776:b 772:a 768:/ 764:a 760:b 758:2 750:2 740:b 736:/ 732:a 724:b 720:a 712:b 708:/ 704:a 695:2 677:d 673:b 669:c 665:a 661:c 657:a 653:b 649:a 632:d 628:/ 624:c 612:b 608:/ 604:a 585:/ 572:3 569:/ 566:2 531:3 528:4 523:= 482:3 479:/ 476:4 454:3 451:4 446:= 441:9 433:= 387:4 384:/ 381:2 371:2 368:/ 365:1 355:2 352:/ 349:1 339:4 336:/ 333:2 320:/ 307:6 304:/ 301:5 291:4 288:/ 285:1 253:d 249:/ 245:c 233:b 229:/ 225:a 217:a 208:a 200:b 194:d 184:a 178:c 167:d 163:/ 159:c 147:b 143:/ 139:a 131:b 127:a 96:b 92:a 84:b 80:a 72:b 68:/ 64:a 20:)

Index

Lowest terms
fraction
integers
divisors
coprime
greatest common divisor
mathematics
rational fractions
polynomials
rational number
absolute value
if and only if
greatest common divisor
Euclidean algorithm
prime factorization
greatest common divisor
unique prime factorization
proofs of the irrationality of the square root of 2
contradiction
field of fractions
unique factorization domain
rational expressions
monic polynomial
Anomalous cancellation
Diophantine approximation
"Fraction"
Encyclopedia of Mathematics
EMS Press
The Legacy of Niels Henrik Abel: The Abel Bicentennial, Oslo, June 3-8, 2002
ISBN

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