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Use properties to find the sum or product. 

 

93+(68+7)

 

5x23x2

 

8x51

 

34+0+18+26

 

6x107

 

 

            

Thanks!!smiley

Guest Jun 27, 2017
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3+0 Answers

 #1
avatar+1214 
+2

1. \(93+(68+7)=93+75=168\)

 

2. \(5*23*2=23*10=230\)

 

Although calculating in this fashion does not adhere to the order of operations, calculating it this way makes it easier mentally. I can use this method because of the commutative property of multiplication, which states that multiplication can be done in any order

 

3. \(8*51=408\)

 

4. \(34+0+18+26=34+18+26=52+26=78\)

 

5. \(6*107=642\)

 

Except for #2, I use order of operations to calculate the sum or product. For number 2, I utilized the commutative property of multiplication.

TheXSquaredFactor  Jun 27, 2017
edited by TheXSquaredFactor  Jun 27, 2017
edited by TheXSquaredFactor  Jun 27, 2017
 #2
avatar+4692 
+2

If by "use properties" you mean find a way to do these in your head, here's my take:

 

93 + 68 + 7                  The 93 and the 7 sum to 100

=  100 + 68

=  168

 

5 * 23 * 2                      5 and 2 multiply to 10

=  10 * 23                     To multiply by 10, move the decimal point right one position.

=  230

 

8 * 51

=  8 * (50 + 1)

=  8 * 50 + 8 * 1

=  8 * 5 * 10 + 8 * 1

=  40 * 10 + 8

=  400 + 8

=  408

 

34 + 0 + 18 + 26           The 34 and 26 sum to 60

=  60 + 18

=  78

 

6 * 107

=  6 * (100 + 7)

=  6 * 100 + 6 * 7

=  600 + 42

=  642

 

I only used the calculator to check these! smiley

 

Also...here is a question for X2 ....why did you say that calculating in this fashion doesn't adhere to the order of operations ?

hectictar  Jun 27, 2017
 #3
avatar+1214 
+2

Well, for #2, I calculated in the exact same manner as you did. I multiplied 5 by 2 first. However, order of operations says that you always calculate from left to right. I didn't do that. 

 

I guess that note causes more confusion that what is intended...

TheXSquaredFactor  Jun 27, 2017

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