1.02a distributive property

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  • 1. 2 x 2 digit Multiplication We are going to learn: 1.02a 2 x 2 digit multiplication 1.02c Different multiplication strategies

2. We are also going to use the Distributive Property 3. Review Commutative Property Changing the order of the factors doesnt change the product Examples? 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, doesnt change the answer. Remember: 8 + (9 +7) = (8 + 9) + 7 (3 x 4) x 5 = 3 x (4 x 5) 6. Lets Try Something New! Solve the following expression: 3 x (4 + 7) 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. 8. Example: 5 x (6 + 4) 9. Different Way What if one of the numbers isnt broken up already? We can use the distributive property with more complicated multiplication. We break up one number to make the multiplication easier. 10. Lets Try: 20 x 56 I dont 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: Lets break up 11 x 17 Which number should we break apart? Why? (10 x 11) = 110 17 ( 7 x 11) = + 77 x 11 187 12. 36 x 22 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