Tuesday

Add and Subtract 10, 100 and 1,000 using Place Value

Using place value, you can add or subtract 10 to a number, or even 100, or EVEN 1,000, pretty easily, just by thinking about the expanded value of the number. 

e.g. 6,578 + 10                          or + 100                                   or + 4,000 



Let's expand it first:
6,000 + 500 + 70 + 8          6,000 + 500 + 70 + 8               6,000 + 500 + 70 + 8 
                    + 10                        + 100                           + 4,000 
= 6,000 + 500 + 80 + 8    = 6,000 + 600 + 80 + 8          =10,000 + 500 + 80 + 8 
= 6,588                                     = 6,688                                   = 10,588 


What a cool trick! 


Play this dice game about adding 10, click on 'add 10.'

Pick a numbers and expand it. Then add:
- 10
- 100
- and other numbers.


It works for subtraction too! Pick the same numbers and try subtraction using expanded forms.



Pick 7 more numbers to ensure you have the hang of it.

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