Mental Math
6 x 7 _____
6x 70 _____
6 x 700 _____
42
420
4,200
This property of math lets us decompose multiplication expressions.
256x741
300 x 700 = 210,000
45.8 + 23.4 =
69.2
20 x 15 =
300
5 x 6 = _____
5 x 60 = ______
50 x 60 = _____
30
300
3,000
This property lets us group numbers within addition and multiplication expressions in way that makes it more efficient.
What is the Associative Property
620 times 450
600 x 500 = 300,000
65.8 - 5.6 =
60.2
472x721 =
340,312
7 x 5 = ____
7 x 50 = ____
7 x 500 = ____
7 x 5000 = _____
35
350
3,500
35,000
This property lets us move numbers around within an addition or multiplication expression.
What is the Commutative Property
390 x 449
400 x 400 = 160,000
750.82 - 497.98 =
252.84
If 472x721 = 340,312, What is 4.72 x 721?
3,403.12
If 12 x 12 = 144, what is 1.2 x 12?
14.4
14 and 4 tenths
The identity property of 1
7,939 × 541 ≈ _________ x ________ ≈
8,000 x 500 = 4,000,000
750.82 + 497.98 =
1,248.80
Ms. Marquez has money to purchase new chairs. She wants to buy 33 chairs at $75.23. How much money will Ms.Marquez end up spending on the chairs?
$2,482.59
If 15 x 15 = 225, what is 1.5 x 1.5?
2.25
Solve 70 x 80 and mention the properties used.
First, I used the Distributive Property to decompose 80 into 8 x 10 and 70 into 7 x 10. Then I used the commutative property to move the 8 and the 10 around, which gave me 7 x 8 x 10 x 10. Lastly, I used the Associative Property to regroup numbers (7x8) x (10x10) which gave me 56 x 100, which equals 5,600.
4,521 × 57 ≈
5,000 x 60 = 300,000
Ms. Márquez bought a Nintendo Wii U for $259.87 while Mr. Banks bought a PlayStation 5 for $467.50. How much money did they spend altogether?
They spent a total of $767.37
Mr. Palacios wants to buy each student a PS5. If there are 28 students in his class and each PS5 costs 500 dollars how much will he spend?
$14,000