SaiBook.us Math

Home Course Section Lesson

Lesson Topics Discussion Quiz: Class Homework

Example1

Title: Fraction Subtraction

Grade Lesson s1-l6

Explanation: The best way to understand SAT-4 is by looking at some examples. Take turns and read each example for easy understanding.

Examples

Topics → Definition Example1

Subtract \$8 15/10\$ − \$4 12/16\$.

Step: 1

First, convert the given mixed fractions into improper fractions.
Now multiply the denominator with a whole number and add the answer to the numerator.
⇒ \$8 15/10\$ = \$95/10\$ ⇒ \$4 12/16\$ = \$76/16\$

$1a$

. https://uat-image.saibook.org/edu/math/psat/v4/psat-core/s1/l6/example1/1a.jpg

Explanation:

Now multiply 8 by 10 and add 15 we get 95. Now multiply 4 by 16 and add 16 we get 76. we get the fractions \$95/10\$ and \$76/16\$.

Step: 2

The denominators are 10 and 16. The least common Multiply (LCM) between 10 and 16 is 80.

$2a$

. https://uat-image.saibook.org/edu/math/psat/v4/psat-core/s1/l6/example1/2a.jpg

Explanation:

The denominators are different in this step, so we need to find the Least Common Multiple (LCM). The LCM of 10 and 16 is 80.

Step: 3

Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal to the LCM. ⇒ \$95/10 \times 8/8\$ = \$760/80\$
⇒ \$76/16 \times 5/5\$ = \$380/80\$

$3a$

. https://uat-image.saibook.org/edu/math/psat/v4/psat-core/s1/l6/example1/3a.jpg

Explanation:

Now multiply \$95/10\$ into \$8/8\$. Now multiply \$76/16\$ into \$5/5\$. we get the fractions to \$760/80\$ and \$380/80\$.

Step: 4

Now that both fractions have the same denominator, subtract the numerators:
⇒ \$760/80 − 380/80\$ = \$380/80\$.
Simplify the resulting fraction by dividing both the numerator and denominator by 20:
⇒ \$380/80 = 19/4\$

$4a$

. https://uat-image.saibook.org/edu/math/psat/v4/psat-core/s1/l6/example1/4a.jpg

Explanation:

Subtract the common denominator 380 from 760 to get \$380/80\$. Simplify by dividing both numerator and denominator by 20, \$19/4\$.

Step: 5

To convert \$19/4\$ into a mixed number, divide 19 by 4, quotient(Whole number) is 4, remainder(numerator) is 3, & divisor(denominator) is 4 :
Mixed fraction = \$"Whole Number" + "Numerator"/"Denominator"\$
So, \$19/4\$ = \$4 3/4\$

$5a$

. https://uat-image.saibook.org/edu/math/psat/v4/psat-core/s1/l6/example1/5a.jpg

Explanation:

By dividing 19 by 4, we get 4 as quotient and remainder as 3. Therefore, the mixed fraction is \$4 3/4\$.