What is (17 - 30) mod 8?

Modulo Arithmetic & Congruence · Question 27 of 97

Question 27

MediumOriginal question

What is $(17 - 30) \bmod 8$ ?

-5

Correct answerYour answer

-3

Correct answerYour answer

3

Correct answerYour answer

5

Correct answerYour answer

Show the answer and explanation

CorrectNot quiteAnswer C

Correct answer: C

$17 - 30 = -13$ , and $-13 = 8 \times (-2) + 3$ .
So $(17 - 30) \bmod 8 = 3$ . Or reduce first: $(1 - 6) \bmod 8 = (-5) \bmod 8 = 3$ .

Worth noting

5 is $13 \bmod 8$ : the minus sign was dropped.

Ten questions from Modulo Arithmetic & Congruence, at your own pace.

Ten questions from Modulo Arithmetic & Congruence, at your own pace.