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 94 have?
- 2.What is the smallest number you must take away from 133 so that it divides exactly by 13?
- 3.What is the smallest number you must add to 604 so that it divides exactly by 6?
- 4.What is the smallest number you must take away from 961 so that it divides exactly by 7?
- 5.What is the smallest number you must take away from 590 so that it divides exactly by 3?
- 6.How many factors does 70 have?
- 7.What is the smallest number you must take away from 940 so that it divides exactly by 3?
- 8.What is the smallest number you must take away from 362 so that it divides exactly by 6?
- 9.What is the smallest number you must add to 244 so that it divides exactly by 13?
- 10.What is the smallest number you must take away from 750 so that it divides exactly by 4?
- 11.How many factors does 87 have?
- 12.What is the smallest number you must add to 436 so that it divides exactly by 3?
- 13.What is the smallest number you must add to 785 so that it divides exactly by 6?
- 14.What is the smallest number you must take away from 485 so that it divides exactly by 12?
- 15.How many factors does 84 have?
- 16.How many factors does 79 have?
- 17.How many factors does 50 have?
- 18.How many factors does 20 have?
- 19.Which of these numbers divides exactly by 8? (a) 9456 (b) 3484 (c) 3181 (d) 6493
- 20.What is the smallest number you must take away from 139 so that it divides exactly by 12?
- 21.Which of these numbers divides exactly by 3? (a) 8298 (b) 3473 (c) 2144 (d) 2282
- 22.Which of these numbers divides exactly by 3? (a) 9476 (b) 2055 (c) 1631 (d) 4565
- 23.What is the smallest number you must take away from 148 so that it divides exactly by 6?
- 24.What is the smallest number you must add to 125 so that it divides exactly by 6?
- 25.How many factors does 71 have?
- 26.How many factors does 88 have?
- 27.What is the smallest number you must add to 257 so that it divides exactly by 13?
- 28.How many factors does 31 have?
- 29.How many factors does 30 have?
- 30.What is the smallest number you must take away from 132 so that it divides exactly by 8?
- 31.How many factors does 56 have?
- 32.What is the smallest number you must take away from 857 so that it divides exactly by 4?
- 33.What is the smallest number you must take away from 223 so that it divides exactly by 7?
- 34.How many factors does 41 have?
- 35.What is the smallest number you must add to 935 so that it divides exactly by 13?
- 36.What is the smallest number you must add to 907 so that it divides exactly by 3?
- 37.What is the smallest number you must add to 896 so that it divides exactly by 6?
- 38.What is the smallest number you must add to 103 so that it divides exactly by 11?
- 39.How many factors does 60 have?
- 40.How many factors does 44 have?
Answer key
- 4
- 3
- 2
- 2
- 2
- 8
- 1
- 2
- 3
- 2
- 4
- 2
- 1
- 5
- 12
- 2
- 6
- 6
- 9456
- 7
- 8298
- 2055
- 4
- 1
- 2
- 8
- 3
- 2
- 8
- 4
- 8
- 1
- 6
- 2
- 1
- 2
- 4
- 7
- 12
- 6
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