EduFarming
Your list · 0हिं

Type at least two letters. Press Esc to close.

↑↓ navigate↵ openTAB cycle filter

Modulo Arithmetic & Congruence · Question 41 of 97

Question 41

HardOriginal question

What is (210+35) mod 7\left(2^{10} + 3^{5}\right) \bmod 7?

Options for question 41

Show the answer and explanation
CorrectNot quiteAnswer B

Correct answer: B

Explanation

  1. 23=8≡12^{3} = 8 \equiv 1, so 210=(23)3⋅2≡22^{10} = (2^{3})^{3} \cdot 2 \equiv 2. And 35=243=7×34+53^{5} = 243 = 7 \times 34 + 5, so 35≡53^{5} \equiv 5.

  2. 2+5=7≡02 + 5 = 7 \equiv 0.

Worth noting

2 and 5 are the two parts' remainders; their sum still has to be reduced.

Concept
The remainder of a sum of powers
Typical time
120 s
Your time
—
The rule this testsModular addition, subtraction and multiplication
Practise this chapter →

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

Practise this chapter →

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