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 31 have?
- 2.How many factors does 65 have?
- 3.What is the smallest number you must add to 747 so that it divides exactly by 4?
- 4.Which of these numbers divides exactly by 6? (a) 3190 (b) 9405 (c) 2508 (d) 3413
- 5.How many factors does 72 have?
- 6.What is the smallest number you must take away from 802 so that it divides exactly by 3?
- 7.How many factors does 16 have?
- 8.How many factors does 92 have?
- 9.How many factors does 29 have?
- 10.What is the smallest number you must take away from 100 so that it divides exactly by 3?
- 11.What is the smallest number you must add to 387 so that it divides exactly by 8?
- 12.What is the smallest number you must add to 334 so that it divides exactly by 6?
- 13.How many factors does 25 have?
- 14.What is the smallest number you must add to 451 so that it divides exactly by 8?
- 15.What is the smallest number you must add to 674 so that it divides exactly by 6?
- 16.How many factors does 61 have?
- 17.What is the smallest number you must add to 970 so that it divides exactly by 6?
- 18.What is the smallest number you must take away from 359 so that it divides exactly by 7?
- 19.How many factors does 45 have?
- 20.Which of these numbers divides exactly by 8? (a) 6648 (b) 3555 (c) 2926 (d) 2766
- 21.How many factors does 88 have?
- 22.Which of these numbers divides exactly by 3? (a) 9836 (b) 1322 (c) 8270 (d) 9657
- 23.How many factors does 35 have?
- 24.How many factors does 15 have?
- 25.Which of these numbers divides exactly by 11? (a) 9514 (b) 4520 (c) 5333 (d) 2805
- 26.Which of these numbers divides exactly by 9? (a) 3004 (b) 1374 (c) 5670 (d) 6580
- 27.Which of these numbers divides exactly by 11? (a) 6632 (b) 2124 (c) 4631 (d) 2293
- 28.What is the smallest number you must add to 676 so that it divides exactly by 8?
- 29.How many factors does 32 have?
- 30.What is the smallest number you must add to 113 so that it divides exactly by 12?
- 31.Which of these numbers divides exactly by 11? (a) 3638 (b) 2442 (c) 1027 (d) 5942
- 32.Which of these numbers divides exactly by 4? (a) 8574 (b) 5217 (c) 4882 (d) 4096
- 33.What is the smallest number you must take away from 201 so that it divides exactly by 9?
- 34.What is the smallest number you must take away from 347 so that it divides exactly by 4?
- 35.Which of these numbers divides exactly by 11? (a) 3206 (b) 3845 (c) 7658 (d) 7942
- 36.How many factors does 55 have?
- 37.How many factors does 63 have?
- 38.What is the smallest number you must add to 100 so that it divides exactly by 6?
- 39.Which of these numbers divides exactly by 9? (a) 1939 (b) 1695 (c) 3204 (d) 3466
- 40.What is the smallest number you must add to 647 so that it divides exactly by 4?
Answer key
- 2
- 4
- 1
- 2508
- 12
- 1
- 5
- 6
- 2
- 1
- 5
- 2
- 3
- 5
- 4
- 2
- 2
- 2
- 6
- 6648
- 8
- 9657
- 4
- 4
- 2805
- 5670
- 4631
- 4
- 6
- 7
- 2442
- 4096
- 3
- 3
- 7942
- 4
- 6
- 2
- 3204
- 1
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