Add and Subtract Fractions with Different Denominators: example 4.70

Subtract: $\frac{7}{15} - \frac{19}{24} .$

Work it out on paper first. Then open the solution one step at a time, and stop as soon as you can finish on your own.

Your turn

The book's Try It right after this example: same idea, new numbers. Only the answer is given.

Subtract: $\frac{13}{24} - \frac{17}{32} .$

How did it go?

	$\frac{7}{15} - \frac{19}{24}$
Find the LCD. 15 is 'missing' three factors of 2 24 is 'missing' a factor of 5
Rewrite as equivalent fractions with the LCD.
Simplify each numerator and denominator.	$\frac{56}{120} - \frac{95}{120}$
Subtract.	$- \frac{39}{120}$
Rewrite showing the common factor of 3.	$- \frac{13 \cdot 3}{40 \cdot 3}$
Remove the common factor to simplify.	$- \frac{13}{40}$

	$\frac{7}{15} - \frac{19}{24}$
Find the LCD. 15 is 'missing' three factors of 2 24 is 'missing' a factor of 5
Rewrite as equivalent fractions with the LCD.
Simplify each numerator and denominator.	$\frac{56}{120} - \frac{95}{120}$
Subtract.	$- \frac{39}{120}$
Rewrite showing the common factor of 3.	$- \frac{13 \cdot 3}{40 \cdot 3}$
Remove the common factor to simplify.	$- \frac{13}{40}$