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Best way to solve this

26 replies

Minuethippo · 04/10/2025 11:35

Hi,

so I did this through trial and error but it takes too long. So whilst I know what the answer is, I was wondering if anyone could tell me the best way to solve this please?

thank you

Best way to solve this
OP posts:
Minuethippo · 07/10/2025 22:29

Bump

OP posts:
Octavia64 · 07/10/2025 22:35

ok, well to start with there are eight letters and nine numbers so we know the puzzle doesn’t use one number.

I’d then draw out a table a bit like this:

F: 1 2 3 4 5 6 7 8 9

and the same for each letter.

then I’d start crossing out what it can’t be.

so for example F plus F plus F gives a 2 digit answer. So F cannot be 1 or 2 or 3 but has to be larger than that.

Octavia64 · 07/10/2025 22:36

next step:

the largest F can be is 9. If F is 9 then T has to be 2 (three nines is 27) so T is either 2 or 1.

so I can now cross out 2 and 1 for every other letter.

Octavia64 · 07/10/2025 22:42

Next, I’m going to think about my three times tables.

we have R plus R plus R equals some number of tens and E.

the three times table ends in:
3,6,9,2 (ending of 12), 5,8,1,4,7,0

R cannot be zero and neither can E as if R was zero then three lots of zero would give zero.

same applies to U. So I can cross out zero for those letters.

Octavia64 · 07/10/2025 22:43

Octavia64 · 07/10/2025 22:36

next step:

the largest F can be is 9. If F is 9 then T has to be 2 (three nines is 27) so T is either 2 or 1.

so I can now cross out 2 and 1 for every other letter.

Whoops, sorry, can’t cross out yet.

Octavia64 · 07/10/2025 22:48

Now we have something that doesn’t seem to make sense.

we have R+R+R gives E but we also seem to have
U+U+U gives E. U and R are not the same number (I assume) so three lots of R must be two digits. So R must be not zero or one or two or three.

we could have carried a one or a two over to the next column.

Octavia64 · 07/10/2025 22:53

We also have O+O+O equals R.

we know R cannot be zero so O cannot be zero.

R cannot be one so O csnnot be 7 (three sevens are 21)
R cannot be two so O cannot be 4 (three fours are 12)
R cannot be three so O csnnot be 1.

Octavia64 · 07/10/2025 22:59

I also now notice that R cannot be 5 because three fives ends in a five.

so R cannot be five. Hence E cannot be five.
hence O cannot be 5.

I now have some relationships.
R can now only be 4,6,7 or 8.
E is the unit digit of R times by 3.
O is whatever gives R as the unit digit when multiplied by 3.

so: (example) if R is 4 then E is 2 and O is 8.

Octavia64 · 07/10/2025 23:01

I also notice that three lots of U plus either 1 or 2 must give a unit digit of E as well.

Octavia64 · 07/10/2025 23:04

If R can be 4,6,7,8 or 9

then E can be 2,8,1,4 or 7

ErrolTheDragon · 07/10/2025 23:08

What age was this homework for?

Octavia64 · 07/10/2025 23:10

It’s either NRich or similar extension material.

we used to do similar in year 7 and 8 to work on problem solving but I’ve seen it used as young as year 4.

Minuethippo · 08/10/2025 09:09

Thanks Octavia

OP posts:
Minuethippo · 08/10/2025 09:09

ErrolTheDragon · 07/10/2025 23:08

What age was this homework for?

It was on a 11+ paper

OP posts:
ErrolTheDragon · 08/10/2025 10:15

Minuethippo · 08/10/2025 09:09

It was on a 11+ paper

Really? Even the analytic approach Octavia began is time consuming, I don’t think there’s enough information for there to be a quick one. I wouldn’t bet there’s one unique solution. Smart kid would leave that one till last and then get as far as time allowed ‘showing working’, I think.

zaxxon · 08/10/2025 11:41

I couldn't even get it to work - obviously am not grammar school material! What was the answer?

Minuethippo · 08/10/2025 15:53

ErrolTheDragon · 08/10/2025 10:15

Really? Even the analytic approach Octavia began is time consuming, I don’t think there’s enough information for there to be a quick one. I wouldn’t bet there’s one unique solution. Smart kid would leave that one till last and then get as far as time allowed ‘showing working’, I think.

I thought the same too. My way of working it out was pretty much trial and error like Octavia and it took far too long. Which is why I wondered if I missed a trick and there’s something I should have spotted before attempting to explain to my kid

OP posts:
Minuethippo · 08/10/2025 15:56

zaxxon · 08/10/2025 11:41

I couldn't even get it to work - obviously am not grammar school material! What was the answer?

FOUR = 4659
THREE= 13977

OP posts:
Octavia64 · 08/10/2025 16:35

Ok so I had another go at this and I reckon there are four solutions. I worked it out on paper so photos to follow. This is basically what I posted already.

Best way to solve this
Octavia64 · 08/10/2025 16:36

Then I tried following through for different values of R. I did R equals 4 first and it does have a solution but only if you allow letters to represent the same numbers which I think is implied by the question to not be correct.

Best way to solve this
ErrolTheDragon · 08/10/2025 16:37

I’ll fess up I asked ChatGPT, to see if that could come up with any shortcut. It didn’t, but offered 2 answers - that one and also 3,659 / 10977

Octavia64 · 08/10/2025 16:41

I then worked through the sum for values of R of 6,7,8 and 9.

i got bored after doing 6 and 7.

r equals 6 again forces some letters to represent the same numbers which I think is implied not to be the case.

Octavia64 · 08/10/2025 16:42

There isn’t a short cut you have to rule out as many values of R as possible by basically doing the sum backwards and using your knowledge of the three times table

columnatedruinsdomino · 08/10/2025 18:12

It’s taken me 45 minutes to work from right to left (R,E,U,O,F,T,H) and starting with R=1 then R=2 etc. Two solutions (FOUR=3659, THREE= 13977) and (FOUR=4659, THREE=10977). I would also love to know a quick way of doing it, apart from starting with R=9 which would have taken less than 5 minutes! Poor students, that’s all I can say…

I have just spotted these answers have already been posted 🤣

Minuethippo · 08/10/2025 18:57

Thanks everyone, it looks like there really is no shortcut!
@Octavia64 thank you for the written images, very helpful

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