Exercise 21 Page 297

When adding or subtracting fractions, they should have the same denominator. In this exercise, we are given two fractions with different denominators. 3/10 - (- 1/4) To add fractions, their denominators need to be the same. Since 20 is the least common denominator of the two fractions, we can multiply both the numerator and denominator of 310 by 2 and - 14 by 5 to create a common denominator. We will start with the first fraction.

3/10

ExpandFrac

a/b=a * 2/b * 2

3* 2/10* 2

Multiply

Multiply

6/20

Let's continue with the second fraction.

- 1/4

ExpandFrac

a/b=a * 5/b * 5

- 1*5/4*5

Multiply

Multiply

- 5/20

Now, since the denominators are the same, we can subtract the fractions.

6/20-(- 5/20)

SubNeg

a-(- b)=a+b

6/20+5/20

AddFrac

Add fractions

6+5/20

AddTerms

Add terms

11/20