Divisibility Rules and Factors Worksheet
The method (Rules and powers): By 3 or 9: the digit sum divides by 3 or 9. By 4: the last two digits. By 8: the last three digits. By 6: even and divisible by 3. By 11: the sums of alternate digits are equal or differ by 11. Number of factors: write n = p^a × q^b …, then the count is (a + 1) × (b + 1) × …. To make n divisible by d: divide, then add (d − remainder) or take away the remainder.
NameDateTime takenScore ___ / 40
- 1.How many factors does 21 have?
- 2.What is the smallest number you must take away from 745 so that it divides exactly by 7?
- 3.Which of these numbers divides exactly by 8? (a) 9346 (b) 3335 (c) 8280 (d) 2734
- 4.Which of these numbers divides exactly by 8? (a) 8293 (b) 5691 (c) 8709 (d) 7136
- 5.How many factors does 52 have?
- 6.Which of these numbers divides exactly by 4? (a) 3962 (b) 2714 (c) 5538 (d) 6316
- 7.How many factors does 16 have?
- 8.How many factors does 19 have?
- 9.What is the smallest number you must add to 685 so that it divides exactly by 12?
- 10.What is the smallest number you must add to 943 so that it divides exactly by 3?
- 11.What is the smallest number you must add to 122 so that it divides exactly by 6?
- 12.Which of these numbers divides exactly by 6? (a) 8532 (b) 6238 (c) 3202 (d) 8182
- 13.Which of these numbers divides exactly by 4? (a) 9960 (b) 8071 (c) 2189 (d) 9165
- 14.Which of these numbers divides exactly by 4? (a) 4275 (b) 8822 (c) 1936 (d) 6121
- 15.How many factors does 87 have?
- 16.How many factors does 42 have?
- 17.What is the smallest number you must take away from 953 so that it divides exactly by 12?
- 18.What is the smallest number you must take away from 971 so that it divides exactly by 9?
- 19.How many factors does 13 have?
- 20.Which of these numbers divides exactly by 6? (a) 2240 (b) 5975 (c) 9138 (d) 5999
- 21.What is the smallest number you must add to 163 so that it divides exactly by 8?
- 22.What is the smallest number you must add to 208 so that it divides exactly by 12?
- 23.What is the smallest number you must add to 502 so that it divides exactly by 7?
- 24.What is the smallest number you must add to 615 so that it divides exactly by 4?
- 25.Which of these numbers divides exactly by 6? (a) 6440 (b) 3185 (c) 6414 (d) 9021
- 26.Which of these numbers divides exactly by 11? (a) 6028 (b) 4127 (c) 5253 (d) 8905
- 27.Which of these numbers divides exactly by 8? (a) 3113 (b) 1900 (c) 3818 (d) 3096
- 28.Which of these numbers divides exactly by 6? (a) 1494 (b) 3215 (c) 5348 (d) 2815
- 29.What is the smallest number you must add to 913 so that it divides exactly by 9?
- 30.Which of these numbers divides exactly by 3? (a) 5567 (b) 7889 (c) 1184 (d) 9447
- 31.Which of these numbers divides exactly by 3? (a) 2684 (b) 2841 (c) 1048 (d) 5165
- 32.Which of these numbers divides exactly by 3? (a) 7522 (b) 5102 (c) 3516 (d) 3508
- 33.What is the smallest number you must add to 786 so that it divides exactly by 12?
- 34.What is the smallest number you must take away from 534 so that it divides exactly by 9?
- 35.What is the smallest number you must add to 474 so that it divides exactly by 4?
- 36.What is the smallest number you must take away from 815 so that it divides exactly by 9?
- 37.Which of these numbers divides exactly by 9? (a) 8937 (b) 1864 (c) 9326 (d) 1102
- 38.What is the smallest number you must add to 584 so that it divides exactly by 13?
- 39.What is the smallest number you must take away from 639 so that it divides exactly by 8?
- 40.What is the smallest number you must take away from 269 so that it divides exactly by 6?
Answer key
- 4
- 3
- 8280
- 7136
- 6
- 6316
- 5
- 2
- 11
- 2
- 4
- 8532
- 9960
- 1936
- 4
- 8
- 5
- 8
- 2
- 9138
- 5
- 8
- 2
- 1
- 6414
- 6028
- 3096
- 1494
- 5
- 9447
- 2841
- 3516
- 6
- 3
- 2
- 5
- 8937
- 1
- 7
- 5
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