Common Core Math Vocabulary

Doubles Minus 1 - Definition with Examples

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What is doubles minus 1? 
Doubles minus 1 is a strategy used to add two consecutive numbers that is, when they are next to each other. 
We simply add the bigger number twice or double it and then, subtract 1 from it, to get the final result.
 

Here, for example, consecutive number 7 and 8 have been added using the doubles minus one strategy. 

Doubles minus one addition strategy consecutive numbers

Here are more examples of the double minus 1 strategy. 

Doubles minus one addition strategy consecutive numbers real life examples

  Fun Facts

  • Doubles minus 1 and doubles plus 1 are also called near doubles strategies. 
 

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Let’s add consecutive soap bubbles,
Adding five and six; there’s no trouble!
Just make the bigger number double,
Subtract 1 from the double of bubbles. 
 

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Have fun with your child by asking them to find the doubles of numbers you say and then use double minus 1 and doubles plus 1 strategies to find the sum of consecutive numbers between 1 and 20.
 

related math vocbaulary Related math vocabulary

 

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