The fractions have unlike denominators. First, find the Least Common Denominator and rewrite the fractions with the common denominator.
LCD(7/18, 2/9) = 18
Multiply both the numerator and denominator of each fraction by the number that makes its denominator equal the LCD. This is basically multiplying each fraction by 1.
(7/18×11)−(2/9×22)=?
Complete the multiplication and the equation becomes
7/18−4/18=?
The two fractions now have like denominators so you can subtract the numerators.
Then:
7−4/18=3/18
This fraction can be reduced by dividing both the numerator and denominator by the Greatest Common Factor of 3 and 18 using
