Draw or write to show two ways to use a doubles fact to find 6+7.

Doublets means when two same single digit number or two digit number are added, we get the result equal to number multiplied by 2.For Example

1+1=1×2=2

2+2=2×2=4

9+9=2×9=18

Now, we have to find sum Using doublets.

First Way

→6+7

=6+6+1

=2×6+1

=12+1

=13

Second way

→6+7

→7-1+7

→7+7-1

→2×7-1

→14-1

=13

irrational, cannot