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 887 so that it divides exactly by 4?
- 2.How many factors does 64 have?
- 3.What is the smallest number you must take away from 300 so that it divides exactly by 7?
- 4.What is the smallest number you must take away from 898 so that it divides exactly by 13?
- 5.What is the smallest number you must add to 571 so that it divides exactly by 9?
- 6.How many factors does 51 have?
- 7.How many factors does 44 have?
- 8.What is the smallest number you must add to 985 so that it divides exactly by 3?
- 9.What is the smallest number you must add to 332 so that it divides exactly by 12?
- 10.How many factors does 72 have?
- 11.How many factors does 54 have?
- 12.How many factors does 33 have?
- 13.How many factors does 56 have?
- 14.How many factors does 42 have?
- 15.What is the smallest number you must add to 385 so that it divides exactly by 3?
- 16.Which of these numbers divides exactly by 6? (a) 3073 (b) 5950 (c) 3888 (d) 4073
- 17.Which of these numbers divides exactly by 6? (a) 3340 (b) 5210 (c) 4482 (d) 8662
- 18.What is the smallest number you must take away from 116 so that it divides exactly by 12?
- 19.How many factors does 49 have?
- 20.What is the smallest number you must add to 653 so that it divides exactly by 13?
- 21.What is the smallest number you must add to 464 so that it divides exactly by 9?
- 22.What is the smallest number you must take away from 416 so that it divides exactly by 6?
- 23.What is the smallest number you must take away from 421 so that it divides exactly by 13?
- 24.What is the smallest number you must add to 545 so that it divides exactly by 12?
- 25.How many factors does 13 have?
- 26.How many factors does 85 have?
- 27.What is the smallest number you must add to 822 so that it divides exactly by 4?
- 28.What is the smallest number you must take away from 330 so that it divides exactly by 7?
- 29.Which of these numbers divides exactly by 11? (a) 7647 (b) 5005 (c) 9390 (d) 9342
- 30.What is the smallest number you must add to 786 so that it divides exactly by 7?
- 31.Which of these numbers divides exactly by 6? (a) 6508 (b) 1770 (c) 4672 (d) 9685
- 32.What is the smallest number you must take away from 505 so that it divides exactly by 12?
- 33.What is the smallest number you must take away from 109 so that it divides exactly by 6?
- 34.How many factors does 20 have?
- 35.What is the smallest number you must add to 752 so that it divides exactly by 11?
- 36.What is the smallest number you must add to 745 so that it divides exactly by 3?
- 37.What is the smallest number you must take away from 845 so that it divides exactly by 12?
- 38.Which of these numbers divides exactly by 8? (a) 1308 (b) 8243 (c) 7756 (d) 6944
- 39.How many factors does 63 have?
- 40.What is the smallest number you must add to 419 so that it divides exactly by 6?
Answer key
- 3
- 7
- 6
- 1
- 5
- 4
- 6
- 2
- 4
- 12
- 8
- 4
- 8
- 8
- 2
- 3888
- 4482
- 8
- 3
- 10
- 4
- 2
- 5
- 7
- 2
- 4
- 2
- 1
- 5005
- 5
- 1770
- 1
- 1
- 6
- 7
- 2
- 5
- 6944
- 6
- 1
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