add and subtracting fractions

Question 1

Find the smallest multiple

Answer 1

Rewrite the fractions as equivalent fractions with the LCM as the denominator.

Question 2

Find the Biggest common multiple

Answer 2

Multiply those factors both numbers have in common. If there are no common prime factors, the Greatest common factor is 1.

Question 3

find the smallest common multiple

Answer 3

Multiply each factor the greatest number of times it occurs in any of the numbers. nine has two three, and 21 has one seven, so we multiply three two times, and seven once. This gives us 63, the smallest number that can be divided evenly by three, nine, and 21.