CONCEPTS - INVEST 5 to LESSON 60

Question 1

When we divide by 10, the digits shift one place to the right.

Although it is the digits that are shifting places, we produce the shift by moving the decimal point. So the decimal shifts one place to the LEFT when dividing by 10.

Answer 1

12.5 ÷ 10 = 1.25

Question 2

When we divide by 100, the digits shift two places to the right.

Although it is the digits that are shifting places, we produce the shift by moving the decimal point. So the decimal shifts two places to the LEFT when dividing by 100.

Answer 2

12.5 ÷ 100 = .125

Question 3

Reducing by grouping factors equal to 1

Answer 3

When the same factor appears in both the dividend and the divisor, they equal 1. In essence, they cancel each other out

Question 4

Common Denominators

Answer 4

When the denominators of two or more fractions are EQUAL, we say the fractions have Common Denominators.

The fractions 4/7 and 2/7 share the denominator 7. So that have a common denominator.

Question 5

Adding Fractions

Answer 5

Fractions that have common denominators can be added by counting the number of parts, by adding the numerators.

Question 6

Adding and subtracting Fractions that do NOT have common denominators

Answer 6

To add or subtract fractions we must first rename the fractions to make the denominators common.

To find the common denominators of any fractions, we need to first find the Common Multiple of the denominators.

The Least Common Multiple of the denominators is the Least Common Denominator of the fractions.

Example: 1/2 - 1/6

with 1/2 and 1/6 the Least Common Multiple is 6.

To get 1/2 to having a 6 as the denominator, we multiply 1/2 by 3/3.

1/2 x 3/3 = 3/6.

Now we can complete the subtraction.

3/6 - 1/6 = 2/6, or 1/3 when reduced.