I'm a bit lost / behind in my number theory class, but hey what can I do but try to catch up.
I'm asked to find the remainder in division by m=3,7,9,11,13 using divisbility tests for 1234567×1089
For division by 3 (and 9), I know that the sum of the digits must be divisible by 3 (or 9).
Immediately it follows that both 3 and 9 do not divide our monster number. To find the remainder, this is what I did though I'm not sure if I am correct.
28 \equiv 1 \mod 3
and so I say that the remainder in division by 3 of 1234567 \times 10^{89} is 1.
For 7,11,13 I see that
123 - 456 + 700 = 367 and that none of 7,11,13 divide 367.
This is where I'm stuck -- the test is developed using the fact that 7*11*13 = 1001 and 1000 \equiv -1 \mod 1001.
Do i set 367 \equiv x \mod 143 ? Or is the remainder in division from 7,11 and 13 all 367 \mod 1001?
No comments:
Post a Comment