okay so i'm sure there's probably a simpler way to do this, but the only way i can think of changing 2 13/25 into a decimal like 2.45 is first changing it into an improper fraction
to do so you have to multiply the whole number by the denominator or bottom number which equals 50
then you put 50 in the numerator and add the 13 which gives you 63 on top and 25 still on bottom: 63/25
now, to change this into a fraction you just divide 63 by 25 because that's what the fraction line means and you get 2.25 (which now i realize we could have just taken 13/25 and gotten .52 and stuck that on the 2 but whatever)
now we subtract 2.52 and 2.45 and get .7 :)
