A math problem for Austrian 10-year-olds

The equations are already arranged in a manner that the unknowns can be solved directly by forward substitution (3s=30 => s=something, 2k+s=20 => 2k=something => k=something,...). I am shocked that so many people in that twitter thread are not able to solve them.

Edit. But this may be a trick question, because in the last equation, what you have is not a pair of shoes, but one single shoe. The same for the thingy wrapped in newspaper.

More shoes than that.

I found this interesting because:

1) It is evil 2) Is it actually teaching math?

Without reading any comments, your first attempt to solve it will most probably be wrong.

23. It is really amazing.

Nope.

Yeah, its evil =(

6s = 30 -> s = 5

2b + 2s = 20 -> 2b = 20 - 10 -> b = 5

4p + 1b = 13 -> 4p = 13 - 5 -> 4p = 8 -> p = 2

------------------------>

1s + ((1b + 2s + 2p) * 1p) = ?

5 + ((5 + 25 + 22) * 2) = ?

5 + ((5 + 10 + 4) * 2) = ?

5 + (19 * 2) = ?

5 + 38 = 43

----------------->

[6s] + [4p + 1b] = 43

65 + 42 + 5 = 43

30 + 8 + 5 = 43

---------------->

[6s] + [4p + 1b] = 43

[6s] + [4p + 1b] =? 1s + ((1b + 2s + 2p) * 1p)

[6s] + [4p + 1b] =? 1s + [(1bp + 2sp + 2p^2)]

[6s] + [4p + 1b] =? 5 + [52 + 252 + 2(2*2)]

[6s] + [4p + 1b] =? 5 + [10 + 20 + 8]

[6s] + [4p + 1b] =? 5 + 38

[6s] + [4p + 1b] =? 43

43 = 43

23

Nope, sorry!