Dividing by 7 (2 Tests)
- FIRST TEST
Take the last digit in a number.
Double and subtract the last digit in your number from the rest of the digits.
Repeat the process for larger numbers.
Example: 357 (Double the 7 to get 14. Subtract 14 from 35 to get 21 which is divisible by 7 and we can now say that 357 is divisible by 7.
- NEXT TEST
Take the number and multiply each digit beginning on the right hand side (ones) by 1, 3, 2, 6, 4, 5. Repeat this sequence as necessary
Add the products.
If the sum is divisible by 7 - so is your number.
Example: Is 2016 divisible by 7?
6(1) + 1(3) + 0(2) + 2(6) = 21
21 is divisible by 7 and we can now say that 2016 is also divisible by 7.
10 comments:
I think that this divisible by 7 rule is kinda of confusing to me when it comes to the second step, but the first step is easy.
Justin Tapper
I find test 1 to be more understandable.It just is a easier process for me and should be for everyone who try's it.=)
anthony7A
lyston
was here
=p
I found the divisible rule also confusing at first but when i started going over it I started to understand the process of getting the answer. But overall it was pretty good.
I think test 1 was the easiest because you had to double the last digit and whatever your answer was you had to subtract that number with another digit. Step 2 was hard.thanks for reading my comment.
The disibility rule was confuseing at first but then i began 2 understand it (test 1 ). The more times i tried it ,the easier it got 2 me.
Devonte Banner .. 7A
I think that we can find it by doing test one because it looks like a the correct way. Just to add I think if the last number is seven it has to be divisible by seven.(for certain problems)
I think the first step was easier. It was a shorter and faster process. I think these " shorter shortcuts" are better for kids because they might forget the longer process. the process was better understanding than 2 .
Sorry Mr. Torres. Grays Craze is me Ricardo Fernandez
Thats my baseball team.
Im just here to say that I think the first rule is a lot easier than the second rule or test. The first rule is less complicated and confusing than the second rule due to the fact that you just have to double the last number snd subtract.
P.S.
Sorry for comenting so late.
Bill Lin
7B
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