Meet the Other Phone. A phone that grows with your child.

Meet the Other Phone.
A phone that grows with your child.

Buy now

Please or to access all these features

AIBU?

Share your dilemmas and get honest opinions from other Mumsnetters.

AIBU to think this KS3 maths homework is a bit hard or am I a bit thick?

70 replies

kicker · 26/11/2018 20:30

A x E = DI, B x E = AE, C x E = C, D x E = IA, E x E = BA,
F x E = E, G x E = JB, H x E = GI, I x E = FB, J x E = AC

OP posts:
cornflakegirl · 26/11/2018 20:50

I A B E are even

GreenEggsHamandChips · 26/11/2018 20:52

I know. It's the bad maths puzzle. I hate it for introducing misconceptions into kids understanding of Algebra .

littlethings99 · 26/11/2018 20:52

from trial and error using J=5 from a PP, and C is 0... E is 8, B is 6, A is 4

Cachailleacha · 26/11/2018 20:53

C=0
F=1
Then we have the tens digit only repeating once, which means E=8 (doesn't work for any other single digit number).
The rest you can work out by substituting what you already know.

onthenaughtystepagain · 26/11/2018 20:53

Looks like a good homework, what I used to call 'airport mathematics', for a start if C x A = C, then A must be 1 but in this list there are two possibilities, F = 1 too, maybe you've a typo?

RedSkyLastNight · 26/11/2018 20:54

CxE=C means E is 1 or C is 0. Must be C is 0 based on other clues.

Then JxE=A0 means J and E are 5 and 2. E can't be 5 based on other clues so E=2 and J=5.

TeenTimesTwo · 26/11/2018 20:54

I'd be tempted to do the rest by trial and error starting with E x E = BA

So If E = 4 then B =1 and A =6 but the I x E = FB doesn't work as FB would need to be even and it isn't.

E=5, B=2, A=5 wrong
E=6, B=3, A=6 wrong
E=7, B=4, A=9 => I x 7= F4 (14, 84 could be right)
E=8, B=6, A =4 => I x 8 = F6 (16, 56)
E=9, B=8, A=1 => Ix9 =F8 (18)

and so on

onthenaughtystepagain · 26/11/2018 20:55

If it’s not Algebra then it’s just nonsense. This isn’t maths - it’s bollocks.

There's a lot of Mathematics in there.it requires using many of the properties of multiplication.

cornflakegirl · 26/11/2018 20:55

G x E = Fifty something - so times tables it's either 54 or 56
If 54 then G=9
But H x E = GI and no even times table goes up to Ninety something (for up to 9x)
So 56, and G is 7, E is 8

Merryoldgoat · 26/11/2018 20:55

So supposedly every letter is a different digit? I’d that the starting point? And you have to work out which is which?

Cachailleacha · 26/11/2018 20:56

A=4
B=6
C=0
D=3
E=8
F=1
G=7
H=9
I=2
J=5

TeenTimesTwo · 26/11/2018 20:56

It is a good maths-logic problem for top set KS3 I would say.
A terrible homework for mid-low set anyone.

littlethings99 · 26/11/2018 20:58

Ah Cach, you beat me to it! Congrats!

Merryoldgoat · 26/11/2018 20:58

@onthenaughtystepagain

I did maths at university - I know the properties of multiplication but there’s no instruction - without a actual instruction you could just say ‘they’re all zero’ and it works.

If, like a PP states that’s they’re the individual digits 0-9 then there’s a tangible starting point.

GreenEggsHamandChips · 26/11/2018 20:58

There's a lot of Mathematics in there.it requires using many of the properties of multiplication.

But it teaches bad algebra and bad notation

GreenEggsHamandChips · 26/11/2018 20:59

@Merryoldgoat

I totally agree. In fact them all being zero is a more mathmatical answer

IWantToUseAnApostrophy · 26/11/2018 21:00

In order A-J: 4,6,0,3,8,1,7,9,2,5.

One you get C and F you can narrow what E must be by considering E*E and discard all but 2.

But it is horrendous as a PP stated. AE is defined algebraically as A*E. They want it to mean 10A+E

Merryoldgoat · 26/11/2018 21:04

@greeneggshamandchips

Please can you explain this? I literally have no idea what it means which really concerns me...

AB does not meant AB like it should in good notation. It meant (Ax10 +B).

Steamedbadger · 26/11/2018 21:05

Damn - beaten to it but agree with Cach. That was fun. Or yes they could all be 0

onthenaughtystepagain · 26/11/2018 21:09

I think there's at least 1 misprint.

C x E = C implies E = 1, the identity
F x E = E Implies F = 1, the identity

E x E = BA implies E is 5-9, to get a 2 digit square number

So there seem to be a number of contradictions.

GreenEggsHamandChips · 26/11/2018 21:11

So a is one digit between 0 and 9 and b is a different digit between 0 and 9. Normally in algebra AB means "A times B", but this puzzle makes no attempt to respect place value (eg tens and units).

There's a lot of maths in it but it us an extremely bad maths homework

TeenTimesTwo · 26/11/2018 21:11

onthe No. you've forgotten about 0, see further upthread.

TeenTimesTwo · 26/11/2018 21:14

But they have been told it is a code
I think it is fine maths homework for a top set KS3.
It is using logic and maths, just not algebra.

It doesn't look like algebra as they are using a x sign and capital letters.

Steamedbadger · 26/11/2018 21:15

It may be that instructions were given (written or oral) that AB means a two digit number with A in the tens column and B in the units column. The use of x suggested to me that would be the case anyway as otherwise the notation would be mixed (sometimes using x and sometimes not)

waterrat · 26/11/2018 21:18

This is the sort of thing that completely put me off school in general ...so humiliating if you don't get it ....