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 take away from 829 so that it divides exactly by 8?
- 2.What is the smallest number you must add to 121 so that it divides exactly by 3?
- 3.How many factors does 41 have?
- 4.What is the smallest number you must add to 505 so that it divides exactly by 9?
- 5.How many factors does 12 have?
- 6.How many factors does 48 have?
- 7.What is the smallest number you must add to 237 so that it divides exactly by 6?
- 8.What is the smallest number you must take away from 200 so that it divides exactly by 11?
- 9.What is the smallest number you must add to 961 so that it divides exactly by 12?
- 10.What is the smallest number you must add to 900 so that it divides exactly by 8?
- 11.How many factors does 60 have?
- 12.What is the smallest number you must add to 647 so that it divides exactly by 13?
- 13.What is the smallest number you must add to 213 so that it divides exactly by 12?
- 14.Which of these numbers divides exactly by 6? (a) 4569 (b) 4536 (c) 3457 (d) 6723
- 15.How many factors does 16 have?
- 16.Which of these numbers divides exactly by 11? (a) 3083 (b) 2794 (c) 2826 (d) 5707
- 17.How many factors does 78 have?
- 18.How many factors does 53 have?
- 19.What is the smallest number you must take away from 846 so that it divides exactly by 13?
- 20.How many factors does 83 have?
- 21.How many factors does 21 have?
- 22.What is the smallest number you must add to 459 so that it divides exactly by 8?
- 23.How many factors does 91 have?
- 24.How many factors does 37 have?
- 25.What is the smallest number you must take away from 906 so that it divides exactly by 7?
- 26.What is the smallest number you must take away from 837 so that it divides exactly by 12?
- 27.What is the smallest number you must add to 255 so that it divides exactly by 11?
- 28.What is the smallest number you must take away from 115 so that it divides exactly by 13?
- 29.How many factors does 36 have?
- 30.How many factors does 67 have?
- 31.What is the smallest number you must add to 405 so that it divides exactly by 7?
- 32.How many factors does 68 have?
- 33.What is the smallest number you must add to 316 so that it divides exactly by 6?
- 34.How many factors does 98 have?
- 35.What is the smallest number you must take away from 494 so that it divides exactly by 4?
- 36.What is the smallest number you must add to 496 so that it divides exactly by 12?
- 37.Which of these numbers divides exactly by 3? (a) 9138 (b) 2450 (c) 7055 (d) 6188
- 38.What is the smallest number you must take away from 505 so that it divides exactly by 3?
- 39.What is the smallest number you must take away from 905 so that it divides exactly by 7?
- 40.Which of these numbers divides exactly by 4? (a) 5238 (b) 3491 (c) 9036 (d) 7930
Answer key
- 5
- 2
- 2
- 8
- 6
- 10
- 3
- 2
- 11
- 4
- 12
- 3
- 3
- 4536
- 5
- 2794
- 8
- 2
- 1
- 2
- 4
- 5
- 4
- 2
- 3
- 9
- 9
- 11
- 9
- 2
- 1
- 6
- 2
- 6
- 2
- 8
- 9138
- 1
- 2
- 9036
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