Prime and Composite Number

In this article, you will learn the concept of prime numbers and composite number.

What is a prime number?

A prime number is a whole number that only has two factors which are itself and one. It means, it is divisible by 1 and itself.

All the prime numbers, except 2, are odd and called odd prime.

Example of Prime Number: 11 is a prime number. The only factors of 11 are 1 and 11.
1×11=11

11 can be divided by only two numbers i.e. 1 and 11 itself.
11/1 = 11
11/11 = 1

What is a composite number?

➤ A composite number has more factors than 1 and itself.

➤ It can also be divided by at least one integer or number.

➤ All even numbers greater than TWO are composite numbers.

➤ All numbers that end with five are divisible by itself. Therefore all numbers that end with 5 and are greater than five are composite numbers.

➤ ‘0’ and ‘1’ are neither a composite number nor a prime number.

Prime and Composite Numbers Free Worksheets

What is the smallest composite number?
4 is the smallest composite number, because it is divisible by more than 1 and itself. Such as: Factors of 4 are 1, 2, and 4.

Example of composite number?

18 is a composite number. It has more factors than just 1 and itself. Factors of 18 are 1, 2, 3, 6, 9 and 18.
18 / 1 = 18
18 / 2 =9
18 / 3 =6
18 / 6 =3
18 / 9 =2
18 / 18 =1

EASY Method Step by Step: How to find factors

Prime and Composite Numbers List

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Prime or Composite Number?

17 ________________

59 ________________

25 ________________

37 ________________

99 ________________

Divisible Rules of Number: 2, 3, 4, 5, 6, 8, 9, 10

The Rule for 2: A number is divisible by 2 If the digit in the one place is an even number. For example: 260, 752, 134, 976, 838.

The Rule for 3: A number is divisible by 3 if the sum of its digits can be divided by 3 (Ex.: 351: 3+5+1 = 9, 9 can be divided evenly by 3. So we can say that 351 is divisible by 3)

The Rule for 4: A number is divisible by 4 if its last two digits are evenly divisible by 4. For example, 4324. The last two digits are 24 and it is evenly divisible by 4. So 4324 is divisible by 4.

The Rule for 5: A number is divisible by 5 if the digit in the one place is 5 or 0 (zero). For example, 450: 450/5=90, 135: 135/5=27.

The Rule for 6: It depends on rule 2 and 3.

The Rule for 8: A number is divisible by 8 if its last three digits are evenly divisible by 8.
For example, 3624: The last 3 digits of 3624 are 624 and it is evenly divisible by 8. So 3624 is divisible by 8.

The Rule for 9: A number is divisible by 9 if the sum of its digits can be divided by 9 For example, 549: The sum of its digits are 5+4+9=18 and 18 is evenly divisible by 9. So 549 is divisible by 9.

The Rule for 10: A number is divisible by 9 if the digit in the one place is 0 (zero).
For example, 950, 250, 120, 2340.

2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101,103,107,109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173,  179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241, 251, 257, 263, 269, 271, 277, 281, 283, 293, 307, 311, 313, 317, 331, 337, 347, 349, 353, 359, 367, 373, 379, 383, 389, 397, 401, 409, 419, 421, 431, 433, 439, 443, 449, 457, 461, 463, 467, 479, 487, 491, 499, 503, 509, 521, 523, 541, 547, 557, 563, 569, 571, 577, 587, 593, 599, 601, 607, 613, 617, 619, 631, 641, 643, 647, 653, 659, 661, 673, 677, 683, 691, 701, 709, 719, 727, 733, 739, 743, 751, 757, 761, 769, 773, 787, 797, 809, 811, 821, 823, 827, 829, 839, 853, 857, 859, 863, 877, 881, 883, 887, 907, 911, 919, 929, 937, 941, 947, 953, 967, 971, 977, 983, 991, 997

4, 6, 8, 9, 10, 12, 14, 15, 16, 18, 20, 21, 22, 24, 25, 26, 27, 28, 30, 32, 33, 34, 35, 36, 38, 39, 40, 42, 44, 45, 46, 48, 49, 50, 51, 52, 54, 55, 56, 57, 58, 60, 62, 63, 64, 65, 66, 68, 69, 70, 72, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 86, 87, 88, 90, 91, 92, 93, 94, 95, 96, 98, 99, 100, 102, 104, 105, 106, 108, 110, 111, 112, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 128, 129, 130, 132, 133, 134, 135, 136, 138, 140, 141, 142, 143, 144, 145, 146, 147, 148, 150, 152, 153, 154, 155, 156, 158, 159, 160, 161, 162, 164, 165, 166, 168, 169, 170, 171, 172, 174, 175, 176, 177, 178, 180, 182, 183, 184, 185, 186, 187, 188, 189, 190, 192, 194, 195, 196, 198, 200, 201, 202, 203, 204, 205, 206, 207, 208, 209, 210, 212, 213, 214, 215, 216, 217, 218, 219, 220, 221, 222, 224, 225, 226, 228, 230, 231, 232, 234, 235, 236, 237, 238, 240, 242, 243, 244, 245, 246, 247, 248, 249, 250, 252, 253, 254, 255, 256, 258, 259, 260, 261, 262, 264, 265, 266, 267, 268, 270, 272, 273, 274, 275, 276, 278, 279, 280, 282, 284, 285, 286, 287, 288, 289, 290, 291, 292, 294, 295, 296, 297, 298, 299, 300, 301, 302, 303, 304, 305, 306, 308, 309, 310, 312, 314, 315, 316, 318, 319, 320, 321, 322, 323, 324, 325, 326, 327, 328, 329, 330, 332, 333, 334, 335, 336, 338, 339, 340, 341, 342, 343, 344, 345, 346, 348, 350, 351, 352, 354, 355, 356, 357, 358, 360, 361, 362, 363, 364, 365, 366, 368, 369, 370, 371, 372, 374, 375, 376, 377, 378, 380, 381, 382, 384, 385, 386, 387, 388, 390, 391, 392, 393, 394, 395, 396, 398, 399, 400, 402, 403, 404, 405, 406, 407, 408, 410, 411, 412, 413, 414, 415, 416, 417, 418, 420, 422, 423, 424, 425, 426, 427, 428, 429, 430, 432, 434, 435, 436, 437, 438, 440, 441, 442, 444, 445, 446, 447, 448, 450, 451, 452, 453, 454, 455, 456, 458, 459, 460, 462, 464, 465, 466, 468, 469, 470, 471, 472, 473, 474, 475, 476, 477, 478, 480, 481, 482, 483, 484, 485, 486, 488, 489, 490, 492, 493, 494, 495, 496, 497, 498, 500, 501, 502, 504, 505, 506, 507, 508, 510, 511, 512, 513, 514, 515, 516, 517, 518, 519, 520, 522, 524, 525, 526, 527, 528, 529, 530, 531, 532, 533, 534, 535, 536, 537, 538, 539, 540, 542, 543, 544, 545, 546, 548, 549, 550, 551, 552, 553, 554, 555, 556, 558, 559, 560, 561, 562, 564, 565, 566, 567, 568, 570, 572, 573, 574, 575, 576, 578, 579, 580, 581, 582, 583, 584, 585, 586, 588, 589, 590, 591, 592, 594, 595, 596, 597, 598, 600, 602, 603, 604, 605, 606, 608, 609, 610, 611, 612, 614, 615, 616, 618, 620, 621, 622, 623, 624, 625, 626, 627, 628, 629, 630, 632, 633, 634, 635, 636, 637, 638, 639, 640, 642, 644, 645, 646, 648, 649, 650, 651, 652, 654, 655, 656, 657, 658, 660, 662, 663, 664, 665, 666, 667, 668, 669, 670, 671, 672, 674, 675, 676, 678, 679, 680, 681, 682, 684, 685, 686, 687, 688, 689, 690, 692, 693, 694, 695, 696, 697, 698, 699, 700, 702, 703, 704, 705, 706, 707, 708, 710, 711, 712, 713, 714, 715, 716, 717, 718, 720, 721, 722, 723, 724, 725, 726, 728, 729, 730, 731, 732, 734, 735, 736, 737, 738, 740, 741, 742, 744, 745, 746, 747, 748, 749, 750, 752, 753, 754, 755, 756, 758, 759, 760, 762, 763, 764, 765, 766, 767, 768, 770, 771, 772, 774, 775, 776, 777, 778, 779, 780, 781, 782, 783, 784, 785, 786, 788, 789, 790, 791, 792, 793, 794, 795, 796, 798, 799, 800, 801, 802, 803, 804, 805, 806, 807, 808, 810, 812, 813, 814, 815, 816, 817, 818, 819, 820, 822, 824, 825, 826, 828, 830, 831, 832, 833, 834, 835, 836, 837, 838, 840, 841, 842, 843, 844, 845, 846, 847, 848, 849, 850, 851, 852, 854, 855, 856, 858, 860, 861, 862, 864, 865, 866, 867, 868, 869, 870, 871, 872, 873, 874, 875, 876, 878, 879, 880, 882, 884, 885, 886, 888, 889, 890, 891, 892, 893, 894, 895, 896, 897, 898, 899, 900, 901, 902, 903, 904, 905, 906, 908, 909, 910, 912, 913, 914, 915, 916, 917, 918, 920, 921, 922, 923, 924, 925, 926, 927, 928, 930, 931, 932, 933, 934, 935, 936, 938, 939, 940, 942, 943, 944, 945, 946, 948, 949, 950, 951, 952, 954, 955, 956, 957, 958, 959, 960, 961, 962, 963, 964, 965, 966, 968, 969, 970, 972, 973, 974, 975, 976, 978, 979, 980, 981, 982, 984, 985, 986, 987, 988, 989, 990, 992, 993, 994, 995, 996, 998, 999, 1000.

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