1.02a distributive property
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Transcript of 1.02a distributive property
2 x 2 digit Multiplication
We are going to learn:
1.02a – 2 x 2 digit multiplication
1.02c – Different multiplication strategies
We are also going to use the
Distributive Property
Review
• Commutative Property – Changing the order of the factors doesn’t change the product
• Examples?
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?
• 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)
Let’s Try Something New!
• Solve the following expression:
3 x (4 + 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.
Example: 5 x (6 + 4)
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.
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)
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
36 x 22
Distributive Property24 x 55
1. Pick one of the numbers to break apart 242. 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.
• Now – you try some examples in your journal.
• Solve the following problems by the breaking apart the underlined number.
47 x 30 63 x 41
12 x 52 23 x 29