A.253
B.213
C.57
D.255
2007-08-31 07:03:48 · 17 answers · asked by NONAME 2 in Science & Mathematics ➔ Mathematics
Check the sum of it's digits. If it is divisible by 3, so is the number.
Therefore, only A is not divisible since 2 + 5 +3 = 10 is not divisible evenly by 3.
2007-08-31 07:08:49 · answer #1 · answered by Chang Y 3 · 0⤊ 0⤋
Just A.
Add up the digits (2 + 5 + 3 = 10). Now see if 10 is divisible by 3 and it's pretty obvious that it isn't. Since the 10 isn't, the original number isn't either. So 253 is not divisible by 3.
Try 255 --> 2 + 5 + 5 = 12 which is divisible by 3 (12 / 3 = 4). That tells me that 255 is divisible without having to actually do the work. (255 / 3 = 85)
John
2007-08-31 14:11:40 · answer #2 · answered by John G™ 3 · 0⤊ 0⤋
"a"
Here's a trick; add all the numbers together, o fthe end result is divisible by 3, then the number is as well.
2+5+3 = 10 1+0 = 1
2+1+3 = 6
5+7 = 12 1+2 =3
2+5+5 = 12 1+2 = 3
The same can be done for 13,257,613,846,132,168,440.
Is it divisible by 3?
1+3+2+5+7+6+1+3+8+4+6+1+3+2+1+6+8+4+4+0 = 75
7+5 = 12
1+2 = 3
2007-08-31 14:20:26 · answer #3 · answered by saberhilt 4 · 0⤊ 0⤋
The answer is A.
1 253/3 = 84.3333...
2 213/3 = 71
3 57/3 = 19
4 255/3 = 85
You could have just used a calculator to see which one didn't divide evenly. Besides, there's one common rule to find out if a number is divisible by 3 or not. It is to add up the digits. For example, if you're finding out if 723 is divisible by 3, just add up 7+2+3, and you get 12. Is 12 divisible by three? Yes! So 723 is divisible by 3 (you get 241). However, if you're finding out weather 235 is divisible by 3, you add up the digits yet again, to get 10. Is 10 divisible by 3? No! Therefore, 235 is not divisible by three (you get 78.333...). Hopefully this helps!!
2007-08-31 14:14:44 · answer #4 · answered by Kobe Bryant 3 · 0⤊ 0⤋
here's the way to tell. add up all the digits. if the result is divisible by 3, then the original number is too.
253 ---> 2+5+3 = 10. 10 is not divisible by 3. so 253 is not
213 ---> 6. 6/3 = 2. so 213 is divisible by 3.
57 ---> 12. 12/3 = 4. so 57 is divisible by 3
255 ---> 12. 12/3 = 4 also divisible by 3
anser is A
2007-08-31 14:10:37 · answer #5 · answered by Dr W 7 · 0⤊ 0⤋
A if the sum of the digits is not divisible by three then the number is not. 2+5+3 = 10
2007-08-31 14:09:03 · answer #6 · answered by chasrmck 6 · 0⤊ 0⤋
A): 253 is not divisible by 3
2007-08-31 14:09:24 · answer #7 · answered by Anonymous · 0⤊ 0⤋
A.253
253/3 = 84.3333333
2007-08-31 14:07:30 · answer #8 · answered by petep73 3 · 0⤊ 0⤋
A): 253 is not divisible by 3, all others are
2007-08-31 14:07:25 · answer #9 · answered by vlee1225 6 · 0⤊ 0⤋
Add up the digits and see if you get a number
divisible by 3.
The digit sums are
A. 10
B. 6
C. 12
D. 12
Since 10 is the only one of these not divisible by 3,
the answer is A. 253.
2007-08-31 16:30:06 · answer #10 · answered by steiner1745 7 · 0⤊ 0⤋