1. Properties of Numbers Use mental math to simplify –2 • 13 • 5.
COURSE 3 LESSON 1-8
Use mental math to simplify –2 • 13 • 5.
What you think
It is easy to multiply with multiples of 10. –2 times 5 is –10, a multiple of
10. –10 times 13 is –130. So, –2 • 13 • 5 = –130.
Commutative Property
Why it works
–2 • 13 • 5 = –2 • 5 • 13
Order of operations
= –10 • 13
Simplify.
= –130
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2. Properties of Numbers Find each product. a. 7(t – 5)
COURSE 3 LESSON 1-8
Properties of Numbers
Find each product.
a. 7(t – 5)
7(t – 5) = 7t – 7 • 5
Distributive Property
Simplify.
= 7t – 35
b. (d + 23)(–4)
(d + 23)(–4) = d(–4) + 23(–4)
Distributive Property
= –4d + (–92)
Simplify.
= –4d – 92
Rewrite as a subtraction expression.
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3. Properties of Numbers Simplify 9 • 13 + 11 • 13. What you think
COURSE 3 LESSON 1-8
Simplify 9 • • 13.
What you think
Combine 9 and 11 first because they are easy to add = 20.
Multiply 20 by 13 to get 260. So, 9 • • 13 = 260.
Distributive Property
Why it works
9 • • 13 = (9 + 11) 13
Order of operations
= (20)13
Simplify.
= 260
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4. Properties of Numbers
COURSE 3 LESSON 1-8
Use the Distributive Property to rewrite each expression.
1. 8(a + 2)
2. –2(3x + 1)
3. 4 • • 3
4. (6 – r)(–4)
5. 5 • • 9
8a + 16
–6x – 2
(4 + 6)3
–24 + 4r
5(1 + 9)
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