what is the remainder when 2^83 is divided by 9
The remainder when 2832^{83}283 is divided by 9 is 5.
Quick Scoop: Core Idea
To find what is the remainder when 2^83 is divided by 9 , notice that powers of 2 repeat in a cycle when taken modulo 9:
- 21=2β2mod 9=22^1=2\Rightarrow 2\mod 9=221=2β2mod9=2
- 22=4β4mod 9=42^2=4\Rightarrow 4\mod 9=422=4β4mod9=4
- 23=8β8mod 9=82^3=8\Rightarrow 8\mod 9=823=8β8mod9=8
- 24=16β16mod 9=72^4=16\Rightarrow 16\mod 9=724=16β16mod9=7
- 25=32β32mod 9=52^5=32\Rightarrow 32\mod 9=525=32β32mod9=5
- 26=64β64mod 9=12^6=64\Rightarrow 64\mod 9=126=64β64mod9=1
So the pattern of remainders for 2nmod 92^n\mod 92nmod9 is:
2, 4, 8, 7, 5, 1 and then it repeats every 6 powers.
This means the cycle length is 6.
Mini Step-by-Step
- We only care about the exponent modulo 6 (because the cycle length is 6).
- Compute 83mod 683\mod 683mod6:
- 6Γ13=786\times 13=786Γ13=78
- 83β78=583-78=583β78=5
- So 83β‘5mod 683\equiv 5\mod 683β‘5mod6.
- That means:
283mod 9=25mod 92^{83}\mod 9=2^5\mod 9283mod9=25mod9
- From the cycle above, 25=322^5=3225=32, and
32Γ·9=3 remainder 532\div 9=3\text{ remainder }532Γ·9=3 remainder 5
so 32mod 9=532\mod 9=532mod9=5.
π Therefore, the remainder when 2832^{83}283 is divided by 9 is 5.
Quick Forum-Style Summary
When people on math and exam forums tackle βwhat is the remainder when 2^83 is divided by 9,β they almost always use the repeating cycle of powers of 2 modulo 9 and reduce the exponent 83 modulo 6 to land on the same answer: 5.
Final Answer: 5
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