Algebra brain teasers are one of the few things that both go viral on Facebook and also give you some hope for humanity. This latest one has over 540,000 comments and almost 14,000 shares. Sure, we may be a self-obsessed species that will engage in celebrity worship right up until the day the Earth blows up, but at least we also like algebra problems involving horseys.

ركزوا جيداً لانه فيها خدعة و الجواب الصحيح هو ????????????????????????????????????????????????????????????????????????????????????????????????????????????

Posted by Nejib Tej on Wednesday, August 17, 2016

The solution is below, but we'll let you work on it first.

Hint: Most of these viral math problems involve overlooking some obvious visual clue that your adult brain missed because it thinks it's soooo smart.

Ready? Here it is: there are two horseshoes and two boots. One boot (or horseshoe) is worth half as much as two boots. That was the big, obvious thing a lot of people missed: there's only one boot in the last line, but two boots in the third line. Some people also forgot BIMDAS (it was called PEMDAS in my day), aka "the order of operations": Brackets, Indices, Multiplication, Division, Addition, Subtraction.

Here's the solution written out:

3xHorse = 30
Horse = 10

Horse + (2Horseshoe) + (2Horseshoe) = 18
10 + 4Horseshoe = 18
4Horseshoe = 8
Horseshoe = 2

(2Horsheshoe) - (2Boot) = 2.
4 - 2Boot = 2
Boot = 1

Boot + Horse x Horseshoe = ???
1 + 10 x 2 = ???
1 + 20 = 21