Answers

2015-09-28T18:20:06+08:00
If we look at the last digit of the numbers, we can easily tell whether they are divisible by 2,4,5,8 or 10
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2015-10-03T12:52:01+08:00
1.) divisibility rules of 2.—
If ones digit is an even number.It is divisible by . 2,190,801242836,132458 are examples of number that are divisible by 2
2.) Divisibility rules of 3. —
If the sum of the digit of the number is divisible by 3 then the number is divisible by 3.

Ex.
387 is divisible by 3
3+8+7=18÷3=6

3.) divisible by 4. —
if the last two digits are divisible by 4 then the number is divisible by 4 . In 8 516 , the last two digits are 1 and 6 ,16 is divisible by 4 , 8516 is divisible by 4
4.) divisible by 5.—
a number is divisible by 5 if the number ends in 5 or 0. 115 and 20520 are divisible by 5.
5.) divisible by 6 —
an even number whose sum is both divisible by 3 and 2 is divisible by 6

Ex. 5748 is divisible by 6 because 5 + 7 + 4 + 8 is equal to 24 which is divisible by both 3 and 2

6.) divisible by 7. —
to find if the number is divisible by 7 subract twice the last digit from the rest if the difference is divisible by 7 then the number is divisible by 7
example :
364:36-(4x2)
36-8=28
28÷7=4
therefore 364 is divisible by 7
364 ÷ 7 =52.

6265: 626-(5x2)
626 - 10=616
616÷7=88
therefore 6265 is divisible by 7
6265÷7= 895

7.)divisible by 8—
is the last three digits are divisible by 8 then the number is divisible by 8 52480 is divisible by 8 because 480 which are the last three digits are divisible by 8

8.) divisible by 9—
is the sum of the digits is divisible by 9 then the number is divisible by 9
the sum of 62874( 6 + 2 + 8 + 7 + 4) is 27 it is divisible by 9 thus 62874 is divisible by 9

9.) divisible by 10—
all numbers ending in 0 are divisible by 10.
examples: 100, 500, 1000, 6000
10.) divisible by 11.
1.) if the difference between the sum of every other digit and the sum of the remaining the digit is 0 it is divisible by 11 176 is divisible by 11 because 1 + 6 = 7 7 - 7 is equal to zero
2.) add the digits in blocks of two from right to left
examples:605: 05 + 6 = 11
11 is divisible by 11
therefore 605 is divisible by 11
605 ÷ 11 =55

11.) divisible by 12—
if the number is divisible by both 3 & 4 then the number is divisible by 12.732 is divisible by 12 because 732 is divisible by 3 and 4

732÷3=244
732÷4=183
732÷12 =61
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