to solve you need to convert 3 1/8 and 1 7/8 improper fractions. wicth is 25/8 and 8/8. then subtract the numerators and keep the denominators the same. it would equal 17/8. and finally you need to convert it back to a mixed number by dividing the numerator by the denominator and putting the remaining as the numerator witch equals 2 1/8
