Two hundred minus three times a number is equal to nine.

I assume you want to know "the number"?

we can write down what you said like this:

200-3x=9

where x is the number.

200-3x=9//moving variables to the left, rest to the right
-3x=9-200//multiply by-1
3x=191//divide by 3
x=63

and that is the answer

If jon had $4.00 then takes away $2.25, then he should have $1.75 left. $4.00 - $2.25 = $1.75 hope this ; )