He collected or credited $100 ($50 each from both parents) to buy a $97 shirt, right? the check and balance would be,
$50 + $50 = $97 + $3 (credit on the left and debit on the right)
Now, there is an equal sign there "=" so whatever is done on the left, should as well be done on the right in order to balance. He used $2 out of the $3 on the right to reduce the credit on the left, hence we subtract $2 from both sides,
$49 + $49 = $97 + $1
so we can see that after paying back $2 what he owes is $98 which totally makes sense from the equation above.

THE CONFUSION: that $1 over there. The teaser added the $1 from the right to the left to make it $48 + $48 + $1 making $99 (from the teaser), correct? But this is wrong, if he should pay one of his parents the last $1, what he should be owing is $97, which of course is what is left on the right,
$49 + $49 - $1 = $97 + $1 - $1
$48 + $49 = $97
so it makes total sense to see that finally, he paid off the remaining $3 to be left with the $97 he used to buy the shirt. But this teaser confused us by taking this $1 and instead of subtracting, it added to the right to make it $99 instead of $97 and then asked us for the remaining $1... Do you get it? Now that one has been cleared, you can find the rest

He collected or credited $100 ($50 each from both parents) to buy a $97 shirt, right? the check and balance would be,
$50 + $50 = $97 + $3 (credit on the left and debit on the right)
Now, there is an equal sign there "=" so whatever is done on the left, should as well be done on the right in order to balance. He used $2 out of the $3 on the right to reduce the credit on the left, hence we subtract $2 from both sides,
$49 + $49 = $97 + $1
so we can see that after paying back $2 what he owes is $98 which totally makes sense from the equation above.

THE CONFUSION: that $1 over there. The teaser added the $1 from the right to the left to make it $48 + $48 + $1 making $99 (from the teaser), correct? But this is wrong, if he should pay one of his parents the last $1, what he should be owing is $97, which of course is what is left on the right,
$49 + $49 - $1 = $97 + $1 - $1
$48 + $49 = $97
so it makes total sense to see that finally, he paid off the remaining $3 to be left with the $97 he used to buy the shirt. But this teaser confused us by taking this $1 and instead of subtracting, it added to the right to make it $99 instead of $97 and then asked us for the remaining $1... Do you get it? Now that one has been cleared, you can find the rest

He collected or credited $100 ($50 each from both parents) to buy a $97 shirt, right? the check and balance would be,
$50 + $50 = $97 + $3 (credit on the left and debit on the right)
Now, there is an equal sign there "=" so whatever is done on the left, should as well be done on the right in order to balance. He used $2 out of the $3 on the right to reduce the credit on the left, hence we subtract $2 from both sides,
$49 + $49 = $97 + $1
so we can see that after paying back $2 what he owes is $98 which totally makes sense from the equation above.

THE CONFUSION: that $1 over there. The teaser added the $1 from the right to the left to make it $48 + $48 + $1 making $99 (from the teaser), correct? But this is wrong, if he should pay one of his parents the last $1, what he should be owing is $97, which of course is what is left on the right,
$49 + $49 - $1 = $97 + $1 - $1
$48 + $49 = $97
so it makes total sense to see that finally, he paid off the remaining $3 to be left with the $97 he used to buy the shirt. But this teaser confused us by taking this $1 and instead of subtracting, it added to the right to make it $99 instead of $97 and then asked us for the remaining $1... Do you get it? Now that one has been cleared, you can find the rest

He collected or credited $100 ($50 each from both parents) to buy a $97 shirt, right? the check and balance would be,
$50 + $50 = $97 + $3 (credit on the left and debit on the right)
Now, there is an equal sign there "=" so whatever is done on the left, should as well be done on the right in order to balance. He used $2 out of the $3 on the right to reduce the credit on the left, hence we subtract $2 from both sides,
$49 + $49 = $97 + $1
so we can see that after paying back $2 what he owes is $98 which totally makes sense from the equation above.

THE CONFUSION: that $1 over there. The teaser added the $1 from the right to the left to make it $48 + $48 + $1 making $99 (from the teaser), correct? But this is wrong, if he should pay one of his parents the last $1, what he should be owing is $97, which of course is what is left on the right,
$49 + $49 - $1 = $97 + $1 - $1
$48 + $49 = $97
so it makes total sense to see that finally, he paid off the remaining $3 to be left with the $97 he used to buy the shirt. But this teaser confused us by taking this $1 and instead of subtracting, it added to the right to make it $99 instead of $97 and then asked us for the remaining $1... Do you get it? Now that one has been cleared, you can find the rest

Pummpy1 wrote I have read this about five times and can not come up with any answer. This is just too confusing.
EDIT

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Shirt = 97. You have no money.
Borrow 50 of a+b Debt to a=50 b=50
You have 100 Debt to a=50 b=50
You buy the shirt for 97 Debt to a=50 b=50
You get 3 change. Debt to a=50 b=50
Give 1 to a+b Debt to a=49 b=49
Right now back to where the mind gets... blown.
49+49=98
Now that is how much you owe them. 49 pound each. Now you don't want to add the pound. The correct way is to take it away. And add towards the cost of the shirt.
98-1=97
97pound+1pound+1pound=100
The pound was never missing

I don't understand any of that, but an easy way to understand it is to imagine getting $100 (or pounds whatever) after you bought the shirt. You give your parents $1 each and keep you keep $1 so you now have $101. Once you give your parents $49 each you are left with $3 and both your parents have the $50 they lent you.

There's no need for crazy math, the topic was just worded oddly.
It's really not that confusing lmao

Ok guys , my brain hurts. I. Think he has the pound left

my dad told me this one and i was sooo confused!! lol

I have seen this before and I never knew, that's why I'm glad people post it in here so now I know it yayayay

uhhhhh I still cant think of anything!

Maybe he lost the pound on the way out of the shop, idk