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 152 so that it divides exactly by 13?
- 2.What is the smallest number you must add to 890 so that it divides exactly by 3?
- 3.What is the smallest number you must add to 109 so that it divides exactly by 7?
- 4.What is the smallest number you must add to 183 so that it divides exactly by 12?
- 5.What is the smallest number you must add to 343 so that it divides exactly by 13?
- 6.How many factors does 46 have?
- 7.Which of these numbers divides exactly by 4? (a) 7363 (b) 5013 (c) 5944 (d) 3337
- 8.What is the smallest number you must take away from 559 so that it divides exactly by 7?
- 9.How many factors does 95 have?
- 10.What is the smallest number you must add to 802 so that it divides exactly by 4?
- 11.How many factors does 15 have?
- 12.What is the smallest number you must add to 402 so that it divides exactly by 7?
- 13.How many factors does 49 have?
- 14.What is the smallest number you must add to 268 so that it divides exactly by 13?
- 15.Which of these numbers divides exactly by 3? (a) 7950 (b) 5276 (c) 9286 (d) 4303
- 16.What is the smallest number you must take away from 979 so that it divides exactly by 4?
- 17.How many factors does 94 have?
- 18.Which of these numbers divides exactly by 3? (a) 8351 (b) 5006 (c) 6519 (d) 4859
- 19.How many factors does 43 have?
- 20.What is the smallest number you must take away from 569 so that it divides exactly by 3?
- 21.Which of these numbers divides exactly by 6? (a) 7789 (b) 2499 (c) 1650 (d) 2464
- 22.What is the smallest number you must add to 262 so that it divides exactly by 3?
- 23.What is the smallest number you must take away from 472 so that it divides exactly by 13?
- 24.How many factors does 32 have?
- 25.What is the smallest number you must add to 260 so that it divides exactly by 7?
- 26.How many factors does 24 have?
- 27.How many factors does 30 have?
- 28.Which of these numbers divides exactly by 11? (a) 4913 (b) 3781 (c) 2805 (d) 3457
- 29.What is the smallest number you must take away from 449 so that it divides exactly by 6?
- 30.Which of these numbers divides exactly by 6? (a) 5638 (b) 1181 (c) 1374 (d) 7807
- 31.What is the smallest number you must take away from 961 so that it divides exactly by 4?
- 32.What is the smallest number you must take away from 742 so that it divides exactly by 8?
- 33.Which of these numbers divides exactly by 4? (a) 2518 (b) 3172 (c) 7495 (d) 9430
- 34.What is the smallest number you must add to 267 so that it divides exactly by 4?
- 35.What is the smallest number you must add to 931 so that it divides exactly by 12?
- 36.What is the smallest number you must add to 462 so that it divides exactly by 4?
- 37.What is the smallest number you must add to 812 so that it divides exactly by 3?
- 38.What is the smallest number you must add to 786 so that it divides exactly by 12?
- 39.What is the smallest number you must take away from 531 so that it divides exactly by 8?
- 40.How many factors does 63 have?
Answer key
- 9
- 1
- 3
- 9
- 8
- 4
- 5944
- 6
- 4
- 2
- 4
- 4
- 3
- 5
- 7950
- 3
- 4
- 6519
- 2
- 2
- 1650
- 2
- 4
- 6
- 6
- 8
- 8
- 2805
- 5
- 1374
- 1
- 6
- 3172
- 1
- 5
- 2
- 1
- 6
- 3
- 6
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