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 99 have?
- 2.What is the smallest number you must take away from 155 so that it divides exactly by 3?
- 3.How many factors does 17 have?
- 4.What is the smallest number you must add to 704 so that it divides exactly by 9?
- 5.What is the smallest number you must take away from 511 so that it divides exactly by 3?
- 6.What is the smallest number you must take away from 410 so that it divides exactly by 11?
- 7.What is the smallest number you must add to 620 so that it divides exactly by 12?
- 8.How many factors does 52 have?
- 9.What is the smallest number you must take away from 912 so that it divides exactly by 13?
- 10.What is the smallest number you must add to 175 so that it divides exactly by 3?
- 11.How many factors does 72 have?
- 12.Which of these numbers divides exactly by 9? (a) 4532 (b) 8967 (c) 7054 (d) 2079
- 13.What is the smallest number you must take away from 385 so that it divides exactly by 3?
- 14.What is the smallest number you must take away from 271 so that it divides exactly by 12?
- 15.Which of these numbers divides exactly by 11? (a) 9778 (b) 1005 (c) 7405 (d) 5170
- 16.What is the smallest number you must take away from 345 so that it divides exactly by 12?
- 17.Which of these numbers divides exactly by 4? (a) 5566 (b) 5950 (c) 8832 (d) 3630
- 18.Which of these numbers divides exactly by 9? (a) 8648 (b) 9936 (c) 8224 (d) 8754
- 19.How many factors does 38 have?
- 20.How many factors does 39 have?
- 21.What is the smallest number you must take away from 172 so that it divides exactly by 8?
- 22.What is the smallest number you must take away from 514 so that it divides exactly by 7?
- 23.How many factors does 95 have?
- 24.How many factors does 61 have?
- 25.How many factors does 90 have?
- 26.Which of these numbers divides exactly by 3? (a) 3193 (b) 8278 (c) 9231 (d) 7859
- 27.Which of these numbers divides exactly by 6? (a) 2702 (b) 5796 (c) 1571 (d) 3607
- 28.What is the smallest number you must add to 467 so that it divides exactly by 3?
- 29.Which of these numbers divides exactly by 11? (a) 6593 (b) 4491 (c) 9729 (d) 5511
- 30.How many factors does 40 have?
- 31.What is the smallest number you must take away from 274 so that it divides exactly by 12?
- 32.How many factors does 82 have?
- 33.How many factors does 88 have?
- 34.Which of these numbers divides exactly by 8? (a) 1369 (b) 4504 (c) 7845 (d) 8507
- 35.Which of these numbers divides exactly by 11? (a) 1413 (b) 4763 (c) 1252 (d) 7584
- 36.What is the smallest number you must add to 486 so that it divides exactly by 8?
- 37.What is the smallest number you must add to 317 so that it divides exactly by 6?
- 38.What is the smallest number you must add to 469 so that it divides exactly by 4?
- 39.What is the smallest number you must take away from 319 so that it divides exactly by 3?
- 40.What is the smallest number you must take away from 846 so that it divides exactly by 7?
Answer key
- 6
- 2
- 2
- 7
- 1
- 3
- 4
- 6
- 2
- 2
- 12
- 2079
- 1
- 7
- 5170
- 9
- 8832
- 9936
- 4
- 4
- 4
- 3
- 4
- 2
- 12
- 9231
- 5796
- 1
- 5511
- 8
- 10
- 4
- 8
- 4504
- 4763
- 2
- 1
- 3
- 1
- 6
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