Help please

[xxbabezxx233]

Decide if the congruent starement is true or false
1788=1155 (mod 5)

Mod 5 in with a clock consisting of 0-1-2-3-4 and I need to know if this statement is true or false

I have a question with mod 6
(12+5)(6+2)(mod6)

a.22
b.6
c.4
d.3


I think it might be 4 for the way i figured is out but I want to make sure thanks

 

[stapel]

Decide if the congruent starement is true or false
1788=1155 (mod 5)

What does "mod 5" mean?

What is 1155-mod-5?

What is 1788-mod-5?

Are they equal?

Mod 5 in with a clock consisting of 0-1-2-3-4 and I need to know if this statement is true or false

I'm sorry, but I don't know what this means. Please clarify this "clock" exercise. Thank you.

I have a question with mod 6: (12+5)(6+2)(mod6)

What is 12 + 5? What is (12 + 5)-mod-6?

What is 6 + 2? What is (6 + 2)-mod-6?

What is the product?

I think it might be 4 for the way i figured...

We'll be glad to check your work, but you'll need to post it first.

Thank you.

Eliz.

 

[xxbabezxx233]

The mod is like using clock arithmatic. if its mod 5 the only numbers you can use is 0-1-2-3-4

 

[Gene]

Those questions of Eliz's weren't for her, they were an invitation for you to think about them and tell her what you found. She knows what mod 5 means. She is trying to prime the pump and get you to tell her what you know. What you have tried. What the results were. She feels she can't teach if she doesn't know what you DON'T know and why you need help.
-----------------
Gene

 

[xxbabezxx233]

I know but thats all I know I dont know how to figure it out is there a formula or something to guide me in the right direction

 

[xxbabezxx233]

I cant quite figure out how to do the 1st one but the second is think might be
12+5=17 in mod 5 equals 1
6+2=8 in mod 5 equals 2

2x1=2

theres no mc for 2?..what am i doing wrong any gudiance would be appreciated

 

[Gene]

That's better. Now we know that you don't understand mod.
x(mod 5) = x-5*ipart(x/5) or
x (mod 5) = 5*fpart(x/5)
where ipart is the result of the division without any decimal part and fpart is only the decimal part
17/5=3.4
17-5*ipart(17/5)=17-(3*5)=2
5*fpart(17/5)=5*.4=2
so 17 (mod 5) = 2
(If you happen to have a TI-83 calc they are under MATH-NUM-3 and MATH-NUM-4)

1788/5=357.6
1788 (mod 5) = 1788-5*357 = 3 or
5*.6=3

That should get you started

 

[xxbabezxx233]

I said mod 5 instead it was mod6 when i recalculate i got 4

i am still confused about the top one one gets a remainder the other one doesnt so i am guessing they are not congruent
No remainder means it is zero (mod n). The question is now does 0 = 3?

 

[Denis]

Perhaps this'll help:
x mod m means: what is the remainder of division x/m

Examples:
17 mod 5 : 17/5 = 3 remainder 2; so 17 mod 5 = 2

35 mod 6 : 35/6 = 5 remainder 5; so 35 mod 6 = 5

 

[pka]

It is really out of date but some abstract algebra textbooks have used this convention:
K = J mod(n) if (K-J) is divisible by n.

This convention means that –17 = 1 mod(6). An algebraist wants this because –17 belongs to the equivalence class determined by 1 in the additive integers modulo 6.

However most calculators or computer algebra systems would give mod(-17,6)=-5.

 

[Denis]

It is really out of date but some abstract algebra textbooks have used this convention:
K = J mod(n) if (K-J) is divisible by n.
This convention means that –17 = 1 mod(6). An algebraist wants this because –17 belongs to the equivalence class determined by 1 in the additive integers modulo 6.
However most calculators or computer algebra systems would give mod(-17,6)=-5.

...and -17\6 = -2 ; -2 * 6 + -5 = -17

Basic language: print -17\6, -17@6 : -2, -5