how would you test to see whether 7 is a factor of 291?

Answer 1

I would divide it out and see.

or

write down the number without the last digit
29
subtract twice the digit you skipped
29
-2
----
27

is 27 divisilbe by 7 ?
no ? , then neither was 291

for large numbers checking for divisibility by 7,
repeat the above process until you can tell.

Not very practical, but it works !!!

Answer 2

why 2 if the end digit is 1?

Answer 3

notice I said, "twice" the number skipped.
2x1 = 2

Answer 4

i don't get it i want ms sue to help me!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Answer 5

<g>

Reiny is a REAL math teacher; I'm not.

I'd just divide 291 by 7.

Answer 6

WOW I BELIEVED IN YOU:P