Question

-18 mod 7

Answer 1

I thought it was -4

Answer 2

but its really 3...

Answer 3

Isnt mod just the remainder of the first operator divided by the second?

Answer 4

Hi jimmyrep

Answer 5

it is all the same

Answer 6

Then why does 18 mod 7 = 4

Answer 7

equivalent is the actual word

Answer 8

But -18 mod 7 = 3?

Answer 9

\[18\equiv 4(\text { mod } 7)\]because
\[18=2\times 7+4\]

Answer 10

\[-18=-3\times 7+3\]

Answer 11

hmm

Answer 12

So is an alternative way of thinking of mod for negative numbers

Answer 13

7 * whatever makes the product closest to the first operand f mod

Answer 14

then the mod is the difference between that product and the first operand of mod

Answer 15

so 7*-3 = -21

Answer 16

-18 - (-21) = 3

Answer 17

yes i think that is a good way to think of it

Answer 18

Ok thanks

Answer 19

these are equivalence classes so you have
\[18\equiv 4(\text{ mod } 7)\equiv 11 (\text { mod } 7) ...\]

Answer 20

So for this http://openstudy.com/#/updates/4eea245be4b0367162f4c98a

Answer 21

the remainder would be 3 also?

Answer 22

-7 mod 5 = 5*-2 +3