Ineed on this one ………..maxwell saved 18$ to buy a finger print kit that costs 99$ he spent 0.25$ of his savings to buy a magnifying glass how much more does he need to save for the finger print kit? ! i don't get it !

Let’s simplify the given situation
Maxwell wants to buy a finger print kit that costs = 99$
His savings is already = 18$
He spent for magnifying glass = 0.25$
X = how much more do Maxwell need to save in order buy a finger print kit that he wants.

=> 99$ - (18$ – 0.25$)
=> Let’s subtract first the digits inside the parenthesis
=> 99$ - 17.75$
=> 81.25$

Therefore, Maxwell still need to save 81.25$ in order to have 99$ and to buy the finger print kit that he always wanted.

He needs to save $99 to buy a finger print kit.
He has already saved $18.
He spent $0.25 from his $18 to buy a magnifying glass.

So, he has currently saved 18 - 0.25, which is 17.75

And so he needs to save 99 - 17.75 to get the finger print kit, which is $81.25

The answer would be b