4. Review
• Identity Property of Multiplication – Any
number times one is that same number.
• Identity Property of Addition – Any number
plus zero is that same number.
• Examples?
5. • Associative Property - Changing the
grouping of the numbers, doesn’t change
the answer.
• Remember:
8 + (9 +7) = (8 + 9) + 7
(3 x 4) x 5 = 3 x (4 x 5)
7. • Use the distributive property to solve the
expression another way…
– Distribute or share the 3 with the 4 and 7.
Check it out:
3 x (4 + 7) = (3 x 4) + (3 x 7)
- Solve the parentheses and then add them
together! The answer is the same.
9. Different Way
• What if one of the numbers isn’t broken up
already?
• We can use the distributive property with
more complicated multiplication. We break
up one number to make the multiplication
easier.
10. Let’s Try: 20 x 56
I don’t mind multiplying with 20
because it has a zero, but 56 is
more difficult! So…
I am going to break up 56
into 50 and 6.
20 x 56 = (20 x 50) + (20 x 6)
11. Another example:
Let’s break up – 11 x 17
Which number should we break apart? Why?
(10 x 11) = 110
17 ( 7 x 11) = + 77
x 11 187
13. Distributive Property
24 x 55
1. Pick one of the numbers to break apart 24
2. Break it apart by:
the value of the tens place – 20
the value of the ones place – 4.
3. Multiply each piece x the second number – 55.
(20 x 55) + (4 x 55)
4. Add the products together.
14. • Now – you try some examples in your
journal.
15. • Solve the following problems by the breaking
apart the underlined number.
47 x 30 63 x 41
12 x 52 23 x 29