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 28 have?
- 2.What is the smallest number you must add to 173 so that it divides exactly by 12?
- 3.What is the smallest number you must take away from 181 so that it divides exactly by 6?
- 4.What is the smallest number you must take away from 509 so that it divides exactly by 13?
- 5.Which of these numbers divides exactly by 4? (a) 4964 (b) 7433 (c) 9102 (d) 9053
- 6.What is the smallest number you must add to 823 so that it divides exactly by 3?
- 7.How many factors does 67 have?
- 8.What is the smallest number you must take away from 353 so that it divides exactly by 7?
- 9.How many factors does 87 have?
- 10.Which of these numbers divides exactly by 11? (a) 8314 (b) 9457 (c) 9339 (d) 7364
- 11.What is the smallest number you must add to 421 so that it divides exactly by 12?
- 12.Which of these numbers divides exactly by 9? (a) 9643 (b) 4371 (c) 6816 (d) 5742
- 13.What is the smallest number you must add to 749 so that it divides exactly by 3?
- 14.What is the smallest number you must add to 259 so that it divides exactly by 9?
- 15.What is the smallest number you must add to 536 so that it divides exactly by 12?
- 16.How many factors does 26 have?
- 17.What is the smallest number you must take away from 180 so that it divides exactly by 13?
- 18.Which of these numbers divides exactly by 4? (a) 7230 (b) 1638 (c) 4845 (d) 6136
- 19.How many factors does 77 have?
- 20.What is the smallest number you must add to 560 so that it divides exactly by 13?
- 21.What is the smallest number you must add to 148 so that it divides exactly by 8?
- 22.Which of these numbers divides exactly by 8? (a) 1998 (b) 1096 (c) 4171 (d) 6522
- 23.How many factors does 31 have?
- 24.How many factors does 32 have?
- 25.What is the smallest number you must add to 410 so that it divides exactly by 7?
- 26.How many factors does 14 have?
- 27.What is the smallest number you must take away from 286 so that it divides exactly by 8?
- 28.How many factors does 57 have?
- 29.Which of these numbers divides exactly by 9? (a) 3414 (b) 7101 (c) 5083 (d) 1803
- 30.What is the smallest number you must take away from 987 so that it divides exactly by 13?
- 31.Which of these numbers divides exactly by 6? (a) 9557 (b) 3382 (c) 5668 (d) 2748
- 32.What is the smallest number you must add to 100 so that it divides exactly by 3?
- 33.Which of these numbers divides exactly by 3? (a) 5521 (b) 2089 (c) 9026 (d) 5295
- 34.How many factors does 36 have?
- 35.What is the smallest number you must add to 152 so that it divides exactly by 13?
- 36.Which of these numbers divides exactly by 3? (a) 4982 (b) 1559 (c) 9001 (d) 7893
- 37.What is the smallest number you must take away from 661 so that it divides exactly by 9?
- 38.Which of these numbers divides exactly by 6? (a) 2993 (b) 9105 (c) 1831 (d) 2844
- 39.What is the smallest number you must add to 493 so that it divides exactly by 4?
- 40.Which of these numbers divides exactly by 9? (a) 9486 (b) 2928 (c) 9750 (d) 3338
Answer key
- 6
- 7
- 1
- 2
- 4964
- 2
- 2
- 3
- 4
- 9339
- 11
- 5742
- 1
- 2
- 4
- 4
- 11
- 6136
- 4
- 12
- 4
- 1096
- 2
- 6
- 3
- 4
- 6
- 4
- 7101
- 12
- 2748
- 2
- 5295
- 9
- 4
- 7893
- 4
- 2844
- 3
- 9486
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