number divisible by 3.

No further division, therefore, is possible.

Step 5.

Multiply the divisors (5, 3, and 2) and remaining quotients (1,

1, 3, and 1). The result is the LCD.

LCD = 5 x 3 x 2 x 1 x 1 x 3 x 1 = 90

The new fractions are 72/90, 75/90, 70/90, and 81/90.

6.

Addition

a.

To add together two or more fractions, first reduce them to

fractions having an LCD (discussed in paragraph 5f).

Then add the

numerators. Next, write the sum of these numerators over the LCD.

EXAMPLE (see figure 6 on the following page)

Add 1/4 + 1/3.

Step 1:

12 is the LCD of 4 and 3

Step 2:

1/4 = 3/12 and 1/3 = 4/12 3/12 + 4/12 = 7/12

b.

add the fractions.

Add the sum of the fractions to the sum of the whole

numbers. If the sum of the fractions is an improper fraction, reduce it to

a mixed number.