Help - children's maths homework

[purplepandas]

Hello,

I am feeling really dim but I have no idea how to tackle this. Any ideas? DD (9) has asked me but I am not clear what they are asking.

Many thanks

So 1 is used once so can either be the star or the teardrop.

2 is used twice so is either the square or the diamond.

And if you have a number ending in a digit, minus another number ending in the same digit, and the result is a third number ending in the same digit - that can only be one thing.

Look the circle. There’s only one of those digits that will work.

Circle must be zero

Really don't know an easy way to work it out, I went through a lot of different combinations before I found one that works

2020-30=1990

That’s the whole point. To work systematically making logical deductions to come up with the answer.

Using the last digit of the big numbers (all circles) you can see that must be zero because it is the only number which, if you take it away from itself, you are still left with the same number.

Then focus on the first digits of the big numbers: one is a square and one is a teardrop. They are different so must the subtraction much change that very first digit. There are two squares, so the only options for square are 9, 3 or 2. It cannot be a 9 because when it gets smaller you would get an 8 for the teardrop but you can't use 8. It can't be 3 because that would leave you with 2 as the teardrop but there is only one teardrop. That means the square must be a 2. This leaves teardrop as 1.

You now have:
2020 - ?0 = 1!!0
And the digits 3 and 9 left. At this point I'd simply try both to see which fits.

Thanks. I get it now if you just have to try options. I thought there was a code I was missing tbh. V grateful.

a) O has to be zero, for reasons stated above.

b) Since a) is true, the diamond has to be 9 because the thousand number changes, and you're only taking away two digits.

c) Similarly, Square - Teardrop = 1

d) Because 2 is used twice the square must = 2 making the Teardrop 1

e) This leaves the star as being 3: 2020 - 30 = 1990