Show:
Order of Operations without Exponents
Order of Operations with Exponents
Identifying Properties
Using Properties to Do "Mental Math"
Mystery Number
100
2 x 8 + 5
What is 21?
100
40 - 2 · 32
What is 22?
100
Name the property: 5 + 7 = 7 + 5
What is the Commutative Property (of Addition)?
100
Explain how to solve using "mental math" 15 + 97 + 85
Possible Answer: Use the Commutative Property to change the order and add 15 + 18 to get 100. Then add 97 to get a sum of 197.
100
The sum of the mystery number and 42 is 87.
What is 45?
200
24 ÷ 4(5 - 3)
What is 3?
200
8 · 4 + 92
What is 113?
200
Name the property: 82 + 0 = 82
What is the Identity Property of Addition?
200
Explain how to solve using "mental math" 97 + (3 + 862)
Possible Answer: Use the Associative Property to change the grouping. Add 97 and 3 to get 100. Then add 862 to get a sum of 962.
200
The difference between the mystery number and 11 is 25.
What is 36?
300
20 - [4(3 +2)]
What is 0?
300
(72 - 32) ÷ 8
What is 5?
300
Name the property: (719)(1) = 719
What is the Identity Property of Multiplication?
300
Explain how to solve using "mental math" (50)(82)(20)
Possible Answer: Use the Commutative Property to change the order and multiply 50 by 20 to get 1000. Then multiply by 82 to get 82,000.
300
Twice the mystery number plus 8 is 30.
What is 11?
400
6[13 - 2(4 +1)]
What is 18?
400
27[52 ÷ (42 + 32) + 2]
What is 81?
400
Name the property: 5 · (9 · 8) = (5 · 9) · 8
What is the Associative Property (of Multiplication)?
400
Explain how to solve using "mental math" 15 + (-20) + 45 + (-80)
Possible Answer: Use the Commutative Property to change the order and add -20 to -80 to get -100. Then add 15 and 45 to get 60. -100 + 60 = -40
400
3 times the sum of the mystery number and 12 is 45.
What is 3?
500
3(6 - 2)
_______
4(2 +1)
What is 1?
500
9 + [4 - (10 - 9)2]3
What is 36?
500
Name the property: 7(9 - 5) = 7 · 9 - 7 · 5
What is the Distributive Property?
500
Explain how to solve using "mental math" The total cost of 5 boxes of rice at $2.95 each.
Possible Answer. Use the Distributive Property as follows:
5($3.00 - $0.05)
5($3.00) - 5($0.05)
$15.00 - $0.25
The total cost is $14.75.
500
3 times the mystery number plus 5 times the mystery number is 72.
What is 9?