Exercise 82 Page 15

Before we can evaluate a sum or difference involving mixed numbers, the mixed numbers must first be rewritten as fractions.

a bc	a* c+b/c	Simplify
73/4	7* 4+3/4	31/4
47/10	4* 10+7/10	47/10

When adding or subtracting fractions, they should have the same denominator. In this exercise, we have two fractions with different denominators. 31/4 - 47/10 To create a common denominator we can multiply both the numerator and denominator of 314 by 5 and 4710 by 2.

31/4-47/10

ExpandFrac

a/b=a * 5/b * 5

31 * 5/4 * 5-47/10

ExpandFrac

a/b=a * 2/b * 2

31 * 5/4 * 5-47 * 2/10 * 2

Multiply

Multiply

155/20-94/20

Now that they have the same denominator, the fractions can be subtracted.

155/20-94/20

SubFrac

Subtract fractions

155-94/20

SubTerms

Subtract terms

61/20