1. 57 2. 92 3. 171 4. 962 5.1,956 6. 11,160
2007-01-12 05:11:12 · 12 answers · asked by kl 1 in Science & Mathematics ➔ Mathematics
Add the digits of the number up. If that's divisible by three, then the number is, too. It's too bad this only works for divisible by three numbers...
1. 57-->5+7=12-->yes
2. 92-->9+2=11-->no
3. 171-->=9-->yes
4. 962-->=17-->no
5. 1956-->=21-->yes
6. 11160-->=9-->yes
2007-01-12 05:21:09 · answer #1 · answered by Lady Irony 2 · 0⤊ 0⤋
There is a quick trick to finding if a number is divisible by 3:
Add all the digits. If the answer is 3, 6, or 9, the number is divisible by 3. If the answer is more than 9, add the digits again until you get something less than ten.
57: 5 + 7 = 12, 1 + 2 = 3 (divisible)
92: 9 + 2 = 11, 1 + 1 = 2 (not divisible)
171: 1 + 7 + 1 = 9 (divisible)
962: 9 + 6 + 2 = 17, 1 + 7 = 8 (not divisible)
1,956: 1 + 9 + 5 + 6 = 21, 2 + 1 = 3 (divisible)
11,160: 1 + 1 + 1 + 6 + 0 = 9 (divisible)
FYI, you can test for divisibility by 9 in exactly the same way... the number is divisible if you get 9 at the end.
2007-01-12 05:20:32 · answer #2 · answered by computerguy103 6 · 0⤊ 0⤋
It's easy. Take a number and add all the digits in it, and keep doing it. If you get a number that's divisible by 3, then the original number is divisible by 3.
So if you have 3,382,320,494
Add all the digits = that gives 38
Add those digits = that gives 11
Since 11 is not divisible by three, your answer is No.
Your last number - 11,160 - works to 9. Which is divisible by 3. So the answer is Yes for the last number.
2007-01-12 05:21:14 · answer #3 · answered by Anonymous · 0⤊ 0⤋
u can find this by adding the digit of a no. if the sum is divisible by 3 then the no. is also divisible
1.57 is divisible (5+7=12)
2.92 is not (9+2=11)
3.171 is divisible (1+7+1=9)
4.962 is not (9+6+2=17)
5.1956 is divisible(1+9+5+6=21)
6.11160 is divisible (1+1+1+6+0=9)
2007-01-12 05:32:36 · answer #4 · answered by hot_ice 2 · 0⤊ 0⤋
An integer is divisible by 3 if and only if the sum
of its digits is divisible by 3.
So, add the digits of each number.
1. 57 digit sum is 12. Yes
2. 923 digit sum is 14. No
3. 171 digit sum is 9. Yes
4. 962 digit sum is 17. No
5. 1956 digit sum is 21. Yes
6. 11160 digit sum is 9. Yes
2007-01-12 05:18:47 · answer #5 · answered by steiner1745 7 · 0⤊ 0⤋
Except the numbers under Sl.No.2 and 4, all the other numbers are divisible by 3. To verify the divisibility by 3, take the sum of all the digits in the number. If the sum is divisible by 3, then the entire number is divisible by 3. Here, you may view the site http://www.geocities.com/gsmani9/divisibility.html for divisibility of other numbers also.
2007-01-12 06:03:56 · answer #6 · answered by mani 2 · 0⤊ 0⤋
If the sum of the digits adds up to 3 or any multiple of 3, then it's divisible by 3.
2007-01-12 05:19:04 · answer #7 · answered by newbie 4 · 0⤊ 0⤋
a number is divisible by 3 if the result of the summition of its digits is Divisible by 3, e.g. 42 is divisible, because 4 + 2 = 6 and that's divisible by 3.
applying the above concept to your numbers :
1) 1.57, 1 + 5 + 7 = 13 not divisible..
etc....
2007-01-12 05:18:44 · answer #8 · answered by Psycho 3 · 0⤊ 1⤋
A number is divisible by 3 only iff the summation i.e. the sum of digits is divisible by 3.For ex. 156 is divisible by 3 as it's sum is divisible by 3.
1.Yes 2.No 3.Yes 4.No 5.Yes 6.Yes
2007-01-12 05:33:47 · answer #9 · answered by MAYUR 1 · 0⤊ 0⤋
Why don't you just get a calculator.
I think if you add up all the digits, and the total is divisible by three, then the number itself is too. Maybe.
2007-01-12 05:19:08 · answer #10 · answered by Lewis 4 · 0⤊ 0⤋