Subsets of Real Numbers
Properties of Real Numbers
Mental Math & Properties
Fractions, Decimals, Percentages
Word Problems
100

Which subset of real numbers includes all the counting numbers?

Natural Numbers

100

What property is illustrated by (4 + 5) + 6 = 4 + (5 + 6)?

Associative Property

100

Is the set of whole numbers closed under subtraction? Justify your answer with a counterexample if false.

False. Counterexample: 4 - 9 = -5, which is a negative integer and not a whole number.

100

Convert the fraction 2/3 into a decimal and a percentage.

Decimal = 0.67, Percentage = 67%

100

A student converted 79% to a decimal and wrote 0.079. What error did they make and what is the correct decimal?

The student moved 3 decimal places to the left instead of 2 decimal places only. The correct decimal is 0.79.

200

What is the most specific subset within the Real Number System for the number -67?

Integer

200

What property is illustrated by 1 + (-1) = 0?

Inverse Property

200

Use the Commutative and Associative Properties of Addition to rearrange and group the numbers below so they are much easier to add. Show your groupings using parentheses and solve the total.

36 + 98 + 24 

(36 +24) + 98 = 60 + 98 = 158

200

Convert 0.55 into a fraction in simplest form and a percentage.

Fraction = 55/100 = 11/20, Percentage = 55%

200

How would you shade a 100-square grid to represent the value of 0.6? 

Shade 60 individual squares out of the 100-square grid (or 6 complete rows/columns out of 10).

300

True or False. The number 0 is a natural number. If false, state the correct subset.

False, 0 is a whole number.

300

Complete the equation using the Identity property of Addition:

32 + __ = 32

0

300

Apply the Distributive Property by filling in the blanks:

15(100 + 4) = (15 × ___ ) + (15 × ___ ) = _______ 

100, 4, 1560

300

Convert 75% into a decimal and a simplified fraction.

Decimal = 0.75, Fraction = 75/100, 3/4

300

Bonus: Multiply the number of thumbs that everyone in the world has. What is the result?

0, because at least one person in the world doesn't have thumbs.

400

Is 0.387 a rational or an irrational number? Explain

Rational because it is a terminating decimal that can be written as a ratio of integers 387/1000

400

Complete the following using the Associative Property of Addition:

12 + (28 + 45) = ?

(12 + 28) + 45

400

Two students evaluated 7 + (8 + 9):

Student A: (7 + 8) + 9

Student B: 7 + (9 + 8)

Which student demonstrated the Associative Property of Addition? Explain.

Student A, because they changed the grouping of the addends using parentheses without altering their order.

400

Which value is greater 2/5 or 35%? Justify your reasoning.

2/5 is greater. 

Reasoning: 2/5 = 0.40 = 40% > 35%

400

A student scored 21 out of 25 on a test and claimed they scored 80%. Evaluate their claim

Their claim is incorrect. Calculation: 21/25 = 84/100 = 84%
500

Why is √10 classified as an irrational number?

Because 10 is not a perfect square, making its decimal representation non-terminating and non-repeating.

500

True or False: The set of non-zero integers is closed under division. If false, provide a counterexample.

False. Counterexample: 5 ÷ 2 = 2.5 or 5.2, which is a rational number/fraction, not an integer.

500

Formulate a numerical expression using parentheses that correctly models the distributed sum (8 × 50) + (8 × 3)

8(50 + 3)

500

Arrange the following rational numbers in ascending order (smallest to largest): 1/2, 0.58, 48%, 0.52.

48%, 1/2, 0.52, 0.58

500

What does a weather forecast of a 55% chance of rain mean based on the definition of percentages?

Out of 100 days with these exact same weather conditions, it is expected to rain on 35 of them.

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