Thank you! I've never heard of this formula. This is great!!!

Let's try 77 / 200. The factors of 231 are 3 X 7 X 11, and those are all prime. Divide the 3 out of 600, and the fraction becomes (7 X 11) / 200.

OMG I have never heard of this rule. It blew my mind. I'm still learning at 68 🤗🤗

good rule that i just couldn't remember. thanks for the refresher.

231/600 I could see straight away that both numbers were divisable by 3 because 2 + 3 +1 = 6 which is a number divisable by 3 giving us 77/200

just divide 2.31 by 6. No need for all that rigmarole!

@laurendoe168

6 ай бұрын

While this will give you a precise decimal answer, you were asked to give a fraction as the solution.

@josebalingitsr.886

6 ай бұрын

perfect!!!

@laurendoe168

6 ай бұрын

@@josebalingitsr.886 Really? Convert 0.385 into a completely reduced fraction because that's the expected answer format.

@James-rn6lo

3 ай бұрын

The right answer is 77/200 .your awnser is not correct

@laurendoe168

3 ай бұрын

@@James-rn6lo 2.31/6 = 77/200

Reduce to what? 77/200 is hardly more useful than the original form. However 231 is 240-9 so we get 240/600 - 9/600 = 4/10 - 3/200 = 400/1000 - 15/100 = 385/1000 (or 0.385) all neat and tidy

@TY-ex5vw

4 ай бұрын

Alternatively, we can use the rules of 3 to reduce to 77/200 and then multiply by 5 to get 77*5/200*5 which is 385/1000=.385

@HartmutWSager

3 ай бұрын

Unnecessary way of dealing with 77/200, since 77/200 = 0.77/2 = .385 (visually obvious). But I sure agree with your comment "reduce to what?".

I did that one weird. I immediately saw that 231= 210 + 21 which was easily divided by 3, as 70 + 7, or 77/200.

@panlomito

6 ай бұрын

Much easier indeed !

Easy. Figured this out in about 10 seconds. I immediately saw that both the numerator and denominator were divisible by 3. How? If you add up all the digits in a number, and the sum is divisible by 3, then the original number is also divisible by 3. In this case, 2 + 3 + 1 = 6. 6 is divisible by 3. If you then divide 231 by 3, you get 77. Dividing 600 by 3 gives 200. 77 = 7 X 11 200 = 2 x 2 x 2 X 5 There are no common factors, so no further simplification is possible. Thus, the final answer is 77/200

I was never taught this. thank you

I can recall,i learned this trick about 70 years ago. Less than 5 second question!

Jó szagú úristen! Ez meg mi volt ? 🙂

231 /600 = 7 7/200 = 0.385

I knew that 3 went into both Something I learned back in grade school

77/200

When I look to simplifying I look for prime factors of the composite numbers. 600 is2*3*100 0r 2*3*2*5*2*5 so I know 231 is not even so 2 is nor a factor nor does it end in 0 or 5 so 5 is not a factor therefore the only possible common factor is a 3 which breaks it down to 3*77 and 77 breaks into 7^11 so 241=3*7*11 or in the end 77/200. Yes I also know the sum of the digits must be divisible by three as do the sums of the sum. like 132675 sums to 18 and that sums to 9 which is also divisible by 3

SO:Learn the divisibility rules to save enormous amounts of time

77over 200 1:07

77/200=•385

Had to use a calculator. Didn't realise that '3' will go into both the nominator and the denominator, leaving a result of 77/200.

Sum of digits in 231 is divisible by 3 so 3 is a common factor 231/3=77 231/600=77/200=38.5/100=0.385

First thought, is 231 prime? So, rule of 3, gives 77. 600/ 3 = 200. Done

2.31

@davidbroadfoot1864

4 ай бұрын

Only if 600 = 100

Thanks. Didn't know the rule of 3.

@GeorgeSmiley77

6 ай бұрын

There's also a rule of 9 - if the sum of the digits is divisible by 9, then the number is divisible by 9. If the sum of the digits is a large number, just repeat the process one more time.

@krisswegemer1163

6 ай бұрын

@@GeorgeSmiley77 Thanks!

.38

1/3

says go ahead and too often

.38 ?

@larry-kp9sp

5 ай бұрын

Percent

No stars???

231/600=77/200

I looked at the factors of 600 and saw that 231 wasn't divisible by 2 or 5, so I tried 3 and found that it went into 231 77 times; hence, I got 77/200.

@stelun56

5 ай бұрын

SO:Learn the divisibility rules to save enormous amounts of time.

231/600 hmmm 231 NOT ÷ by 2..but 3?? 231÷3= 77 600÷3=200 77 = 7÷11 both prime and 200 NOT ÷ BY 7 OR 11 final answer = 77÷200 but.... 77÷100 = 0.77 [in my head] 0.77÷2 = 0.385 [in my head]6 final answer#2 = 0.385 Verify 232/600 = 0.385 (calculator)✔️

🙏🏾

Arithmetic IS Algebra!

(3*77)/(3*200) = 77/200

77/200 if you do this last .ok

This is for third grade student

Please, go straight to the point!

For this specific problem: I see 231/600 as 2.31 divided by 6. This is a simple division problem. The answer = 0.385. Yes, there are other methods. The goal is to use the simplest method for the problem in front of you.

Spends 15 minutes telling you that a number is divisible by 3 if its digits add up to 3. Doesn't bother explaining why.

Can't you just get to the point and stop waffling

77/200

77/200

77/200