DIVISIBILITY TEST
DIVISIBILITY TEST:Specific Objectives
By the end of the topic the learner should be able to:
The learner should be able to test the divisibility of numbers by 2, 3, 4, 5, 6, 8, 9, 10 and 11.
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Content
Divisibility test of numbers by 2, 3, 4, 5, 6, 8, 9, 10 and 11
Introduction
Divisibility test makes computation on numbers easier. The following is a table for divisibility test.
| Divisibility Tests | Example |
| A number is divisible by 2 if the last digit is 0, 2, 4, 6 or 8. | 168 is divisible by 2 since the last digit is 8. |
| A number is divisible by 3 if the sum of the digits is divisible by 3. | 168 is divisible by 3 since the sum of the digits is 15 (1+6+8=15), and 15 is divisible by 3. |
| A number is divisible by 4 if the number formed by the last two digits is divisible by 4. | 316 is divisible by 4 since 16 is divisible by 4. |
| A number is divisible by 5 if the last digit is either 0 or 5. | 195 is divisible by 5 since the last digit is 5. |
| A number is divisible by 6 if it is divisible by 2 AND it is divisible by 3. | 168 is divisible by 6 since it is divisible by 2 AND it is divisible by 3. |
| A number is divisible by 8 if the number formed by the last three digits is divisible by 8. | 7,120 is divisible by 8 since 120 is divisible by 8. |
| A number is divisible by 9 if the sum of the digits is divisible by 9. | 549 is divisible by 9 since the sum of the digits is 18 (5+4+9=18), and 18 is divisible by 9. |
| A number is divisible by 10 if the last digit is 0. | 1,470 is divisible by 10 since the last digit is 0. |
| A number is divisible by 11 if the sum of its digits in the odd positons like 1st ,3rd ,5th ,7th Positions, and the sum of its digits in the even position like 2nd , 4th ,6th ,8th positions are equal or differ by 11,or by a multiple of 11 |
8,260,439 sum of 8 +6 +4 +9 =27:
2 + 0 +3 = 5 ; 27 – 5 = 22 which is a multiple of 11 |
ALL MATHEMATICS NOTES FORM 1-4 WITH TOPICAL QUESTIONS & ANSWERS PRIMARY NOTES, SCHEMES OF WORK AND EXAMINATIONS