425 is decreased to 319.
The above statement means that a number should be deducted from 425 to get the difference of 319.
Let x be the unknown number.
425 - x = 319
425 - 319 = x
106 = x
106 is the unknown number.
It can be phrased like this: 425 decreased by 106 is 319.
This is a right triangle, the measure of angle A is 90 degrees.
First thing to do I guess is finding B and C.
tan^-1 (7/12) = 30 degrees
tan^-1 (12/7) = 60 degrees
60 + 30 = 90
180 - 90 = 90. Therefore angle A = 90 degrees
Each calculator would cost 30 dollars (sorry if this isn't what you mean)