Displaying, Explaining, and Justifying Mathematical Ideas and Arguments Using Precise Mathematical Language

Complete the table with the proper justifications.

c

a

Multiplicative Identity

Subtraction Property of Equality

Division Property of Equality

Multiplication Property of Equality

Addition Property of Equality

Simplify

Additive Identity Property

What is the reason for step 1

The principal surveyed a random sample of 120 students about table tennis. The results are shown in the table. If the high school has 450 seventh-grade students and 350 eighth-grade students, approximately how many students in total would be expected to want to play table tennis?

• 44

• 146

• 136

• 282

What is the reason?

• Transitive Property of Equality

• Substitution Property

• Reflexive Property of Equality

• Addition Property of Equality

Tags

CCSS.HSA.REI.A.1

• No, because it should be multiplied by a power of 20.

• Yes, because it has a decimal and an exponent

• No, because the number is less than 10

• Yes, because the number is between 1 and 10 and being multiplied by a power of 10.

• A
• B
• C
• D

Tags

CCSS.HSS.IC.A.1

CCSS.HSS.IC.B.4

What is the reason for step 4

Answer explanation

This is the addition property.

Why? Because you are adding some amount to both sides of the equal sign

Solve for x and find the side lengths

Answer notation:

x=

a=

b=

• No, because it should be multiplied by a power of 20.

• Yes, because it has a decimal and an exponent

• No, because the number is less than 10

• Yes, because the number is between 1 and 10 and being multiplied by a power of 10.

Tags

CCSS.6.EE.A.1

Justify step #5 (justify means provide the reason).

• Subtraction Property of Equality and then Simplify

• Addition Prop. of Eq. and then Simplify

• Combine Like Terms

• Definition of Angle Bisector and then Simplify