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.What is the smallest number you must add to 408 so that it divides exactly by 9?
- 2.What is the smallest number you must add to 646 so that it divides exactly by 3?
- 3.What is the smallest number you must take away from 649 so that it divides exactly by 12?
- 4.What is the smallest number you must take away from 566 so that it divides exactly by 6?
- 5.How many factors does 14 have?
- 6.How many factors does 77 have?
- 7.What is the smallest number you must add to 631 so that it divides exactly by 4?
- 8.What is the smallest number you must take away from 682 so that it divides exactly by 3?
- 9.What is the smallest number you must take away from 525 so that it divides exactly by 6?
- 10.What is the smallest number you must add to 949 so that it divides exactly by 7?
- 11.Which of these numbers divides exactly by 6? (a) 2872 (b) 5621 (c) 1770 (d) 5528
- 12.What is the smallest number you must take away from 902 so that it divides exactly by 12?
- 13.Which of these numbers divides exactly by 6? (a) 5927 (b) 7010 (c) 3802 (d) 3396
- 14.How many factors does 79 have?
- 15.How many factors does 90 have?
- 16.What is the smallest number you must take away from 213 so that it divides exactly by 13?
- 17.Which of these numbers divides exactly by 3? (a) 2199 (b) 9925 (c) 5675 (d) 6319
- 18.Which of these numbers divides exactly by 9? (a) 3545 (b) 8176 (c) 6147 (d) 9655
- 19.What is the smallest number you must take away from 474 so that it divides exactly by 4?
- 20.What is the smallest number you must take away from 584 so that it divides exactly by 11?
- 21.What is the smallest number you must add to 256 so that it divides exactly by 7?
- 22.What is the smallest number you must take away from 463 so that it divides exactly by 9?
- 23.What is the smallest number you must add to 237 so that it divides exactly by 11?
- 24.What is the smallest number you must take away from 293 so that it divides exactly by 4?
- 25.What is the smallest number you must take away from 332 so that it divides exactly by 6?
- 26.How many factors does 91 have?
- 27.How many factors does 88 have?
- 28.How many factors does 25 have?
- 29.What is the smallest number you must take away from 907 so that it divides exactly by 6?
- 30.How many factors does 66 have?
- 31.What is the smallest number you must add to 873 so that it divides exactly by 12?
- 32.How many factors does 84 have?
- 33.What is the smallest number you must add to 853 so that it divides exactly by 6?
- 34.What is the smallest number you must take away from 786 so that it divides exactly by 13?
- 35.How many factors does 73 have?
- 36.How many factors does 61 have?
- 37.Which of these numbers divides exactly by 4? (a) 8852 (b) 8945 (c) 1689 (d) 5165
- 38.What is the smallest number you must add to 276 so that it divides exactly by 9?
- 39.What is the smallest number you must add to 396 so that it divides exactly by 7?
- 40.How many factors does 26 have?
Answer key
- 6
- 2
- 1
- 2
- 4
- 4
- 1
- 1
- 3
- 3
- 1770
- 2
- 3396
- 2
- 12
- 5
- 2199
- 6147
- 2
- 1
- 3
- 4
- 5
- 1
- 2
- 4
- 8
- 3
- 1
- 8
- 3
- 12
- 5
- 6
- 2
- 2
- 8852
- 3
- 3
- 4
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