SPI 2.1 and 2.2 Comparing and Ordering Real Numbers Coach Lesson 3

Question 1

1

The real numbers are composed of _______ and _______.

Answer 1

rational numbers

irrational numbers

Question 2

2

To compare numbers use inequality symbols.

> is called _______________

< is called _______________

Answer 2

> greater than

< less than

Question 3

3

How do you compare a fraction and a decimal?

• For example, 4/5 and 0.75?

Answer 3

Convert one number to the form of the other.

• 4/5 is 0.80
• 0.75 is 3/4
• 0.80 > 0.75
• Therefore, 4/5 > 0.75

Question 4

4

How do you convert a percent to a decimal?

• For example 78%?

Answer 4

Percent means “per 100”.

1. Rewrite as percent / 100
   * 78/100
2. Divide
   * 0.78 so 78 % is equal to 0.78.

Percents can quickly be converted to decimals by moving the decimal point two places to the left.

Question 5

5

How do you order a list of numbers from least to greatest?

• For example, -15%, 1.5, square root of 2, -1.3

Answer 5

1. Separate the negative numbers from the positive numbers.
   * Negative numbers: -15%, -1.3; Positive numbers: 1.5, square root of 2
2. Convert to decimals.

• -15% is -0.15 and -1.3 is already a decimal
• 1.5 is already a decimal and square root of 2 is about 1.41

3. Then compare, order decimals, and rewrite original numbers in order.

• -1.3, -0.15, 1.41, 1.5
• -1.3, -15%, square root of 2, 1.5