# Least common denominator calculator

### What is LCD?

The lowest common denominator or least common denominator (abbreviated LCD) is the least common multiple of the denominators of a set of fractions. LCD is the smallest positive integer that has multiple denominators in the set. Fractions write with fraction bar / like 3/4.**Example:** for LCD calculation of three fractions 1/2 2/3 5/4, enter 1/2 2/3 5/4.

### How to calculate LCD

The same fraction we can express in many different forms. If the ratio between the numerator and denominator is the same, the fractions represent the same rational number.The least common denominator of a set of fractions is the least number that is a multiple of all the denominators: their "least common multiple".

The method of calculating the LCD is the same as the calculation least common multiple of fractions denominators.

The simple method for common computing denominators (not least at all) is to multiply all denominators.

## Questions and word problems to LCD

- LCD 2

The least common denominator of 2/5, 1/2, and 3/4 - Fractions

Sort fractions z_{1}= (20)/(9); z_{2}= (10)/(21); z_{3}= (15)/(14) by their size. The result writes as three serial numbers 1,2,3. - Preparatory 3222

Less than 50 pupils go to 9A class. A third of the pupils wrote the preparatory test with a one, a quarter with a two, no one wrote with a three, and nine pupils with a four. How many students from 9A wrote the test with a five? - Centipede 4257

Centipede Mirka consists of a head and several articles. Each pair has one pair of legs. When it got cold, she decided to get dressed. Therefore, she put on a sock on her left foot in the third article from the end and then on every other third article. S

- Two gears

The gearbox will use a large gear to turn a smaller gear. The large gear will make 75 revolutions per minute, while the smaller gear must make 384 revolutions per minute. Find the smallest number of teeth each gear could have. [Hint: Use either GCF or LCM - Calculate 81492

Jirka went on a moped for a three-day trip. He drove 90 km on the first day, 30 km on the second day, and 60 km on the third day. He always drove at the same average speed and always the whole number of hours. Calculate the average speed if Jirka drove at - LCD two fractions

What is the least common denominator of 11/15 and 12/19? - Pardubická 4651

Jirka decided to divide the winnings from the bet in Velká Pardubická between himself and his three younger brothers according to age in the ratio of 2:3:5:7. They paid each amount in whole crowns. One of the amounts was CZK 679. How big was the win? - Determine 6

Determine the least common denominator 3/4 and -5/6

- Treasury 73334

Peter has only two crowns in the treasury and can divide them both in a ratio of 4:5 and in a ratio of 4:7. How many crowns does Peter have in the money box if the amount saved is less than 300 CZK? - Meadow

On the meadow grazing horses, cows, and sheep, together with less than 200. If cows were 45 times more, horses 60 times more, and sheep 35 times more than there are now, their numbers would equal. How many horses, cows, and sheep are on the meadow togethe - Ratio

Alena collected 7.8 kg of blueberries, 2.6 kg of blackberries, and 3.9 kg of cranberries. Express the ratio in the smallest natural numbers in this order. - Compare three fractions

Which of the three rational numbers is the largest? 1/7, 6/17, 4/17 - Reminder and quotient

There are given numbers A = 135, B = 315. Find the smallest natural number R greater than one so that the proportions R:A, R:B are with the remainder 1.

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