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 66 have?
- 2.Which of these numbers divides exactly by 6? (a) 7642 (b) 1669 (c) 3755 (d) 6900
- 3.What is the smallest number you must add to 287 so that it divides exactly by 12?
- 4.What is the smallest number you must take away from 177 so that it divides exactly by 8?
- 5.What is the smallest number you must add to 115 so that it divides exactly by 6?
- 6.How many factors does 19 have?
- 7.How many factors does 26 have?
- 8.What is the smallest number you must add to 695 so that it divides exactly by 3?
- 9.Which of these numbers divides exactly by 9? (a) 7193 (b) 7708 (c) 5983 (d) 4590
- 10.What is the smallest number you must add to 291 so that it divides exactly by 7?
- 11.What is the smallest number you must add to 689 so that it divides exactly by 4?
- 12.What is the smallest number you must add to 777 so that it divides exactly by 12?
- 13.What is the smallest number you must add to 217 so that it divides exactly by 13?
- 14.How many factors does 53 have?
- 15.Which of these numbers divides exactly by 8? (a) 6117 (b) 4938 (c) 4055 (d) 8216
- 16.How many factors does 99 have?
- 17.What is the smallest number you must take away from 776 so that it divides exactly by 12?
- 18.Which of these numbers divides exactly by 8? (a) 2585 (b) 8136 (c) 9178 (d) 2730
- 19.What is the smallest number you must take away from 713 so that it divides exactly by 4?
- 20.Which of these numbers divides exactly by 11? (a) 2959 (b) 2554 (c) 2736 (d) 4109
- 21.What is the smallest number you must add to 281 so that it divides exactly by 8?
- 22.How many factors does 93 have?
- 23.What is the smallest number you must add to 211 so that it divides exactly by 6?
- 24.What is the smallest number you must take away from 492 so that it divides exactly by 13?
- 25.How many factors does 48 have?
- 26.What is the smallest number you must add to 778 so that it divides exactly by 7?
- 27.Which of these numbers divides exactly by 11? (a) 1162 (b) 8463 (c) 4858 (d) 2574
- 28.What is the smallest number you must add to 742 so that it divides exactly by 6?
- 29.How many factors does 45 have?
- 30.What is the smallest number you must add to 993 so that it divides exactly by 13?
- 31.How many factors does 27 have?
- 32.What is the smallest number you must take away from 603 so that it divides exactly by 8?
- 33.What is the smallest number you must take away from 755 so that it divides exactly by 11?
- 34.How many factors does 98 have?
- 35.Which of these numbers divides exactly by 8? (a) 3004 (b) 2805 (c) 1898 (d) 5264
- 36.What is the smallest number you must take away from 833 so that it divides exactly by 8?
- 37.What is the smallest number you must add to 729 so that it divides exactly by 11?
- 38.What is the smallest number you must add to 249 so that it divides exactly by 12?
- 39.How many factors does 87 have?
- 40.What is the smallest number you must add to 626 so that it divides exactly by 3?
Answer key
- 8
- 6900
- 1
- 1
- 5
- 2
- 4
- 1
- 4590
- 3
- 3
- 3
- 4
- 2
- 8216
- 6
- 8
- 8136
- 1
- 2959
- 7
- 4
- 5
- 11
- 10
- 6
- 2574
- 2
- 6
- 8
- 4
- 3
- 7
- 6
- 5264
- 1
- 8
- 3
- 4
- 1
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